Wasabi Mango QHD275 Universal
Simon Baker, 30 June 2015

 

Twitter: Stay up to date: @TFTCentral |    Forum: Discuss this review  | RSS Feed: Review Alerts


Introduction

The unusually-named brand Wasabi Mango comes out of Korea, offering a range of low cost monitor options to rival those offered by the likes of Yamakasi, QNIX and Achieva. We've not really heard much about Wasabi Mango before, but were approached by them about conducting a review of their 27" QHD275 Universal display (referred to throughout this review simply as the QHD275 for ease). It's based around an IPS panel, offering a 2560 x 1440 resolution, decent spec and good connectivity options - all at a nice low cost. We've not been very impressed with most of the Korean displays we've tested over the years so we are interested to see if Wasabi Mango can offer anything different here.

If you appreciate the review and enjoy reading and like our work, we would welcome a donation to the site to help us continue to make quality and detailed reviews for you.

 


Specifications and Features

The following table gives detailed information about the specs of the screen:

Monitor Specifications

Size

27"WS (68.47 cm)

Panel Coating

Light AG coating

Aspect Ratio

16:9

Interfaces

1x DisplayPort 1.2

2x HDMI

1x DL-DVI

Resolution

2560 x 1440

Pixel Pitch

0.233 mm

Design colour

Glossy black bezel and base

Response Time

6ms G2G

Ergonomics

Tilt only

Static Contrast Ratio

1000:1

Dynamic Contrast Ratio

50 million:1

VESA Compatible

Yes 100mm

Brightness

380 cd/m2

Accessories

Power cable and brick, DL-DVI and audio cables, remote control

Viewing Angles

178 / 178

Panel Technology

LG.Display IPS

Weight

not listed

Backlight Technology

W-LED

Physical Dimensions

not listed

Colour Depth

16.78m (8-bit)

Refresh Rate

60Hz

Special Features

2x 2W speakers, headphone socket, audio in connection, remote control, PiP / PbP

Colour Gamut

Standard gamut
~sRGB

The QHD275 offers a decent range of connectivity options with DisplayPort, 2x HDMI and Dual-link DVI provided. The digital interfaces are HDCP certified for encrypted content and the video cables are provided in the box for DL-DVI only. Good to see a range of connectivity options offered here considering the low retail price of the display and the fact a lot of screens tend to limit themselves in this area when cutting costs.

The screen has an external power supply brick which is provided of course. There are some basic 2x 2W stereo speakers included, an audio input and headphone output connection, and even a remote control. There aren't any USB ports on this model, or other extras like ambient light sensors or motion sensors.

Below is a summary of the features and connections of the screen:

Feature

Yes / No

Feature

Yes / No

Tilt adjust

DVI

Height adjust

HDMI

Swivel adjust

D-sub

Rotate adjust

DisplayPort

VESA compliant

Component

USB 2.0 Ports

Composite

USB 3.0 Ports

Audio connection

Card Reader

HDCP Support

Ambient Light Sensor

MHL Support

Human Motion Sensor

Integrated Speakers

Touch Screen

PiP / PbP

Factory Calibration

Blur Reduction Mode

Hardware calibration

G-Sync

Uniformity correction

FreeSync



Design and Ergonomics


Above: front and rear views of the screen. Click for larger versions

The QHD275 comes in an all black design with glossy plastics used for the front bezel, stand and base. The bezel measures ~25mm along the top and sides, and ~38mm along the bottom edge. It is fairly chunky as a result. There is a Wasabi Mango logo in the middle of the bottom bezel and the "QHD275 Universal" product name in the top left hand corner as you can see from the photo above. The sticker carrying various logos for things on the right hand edge can be removed if you want. The OSD control labels are also on the front of the screen as you can see, in the bottom right hand corner.

The back of the screen is finished in a matte black plastic. The stand attaches at the bottom of the screen but can be removed if you want. VESA 100 mounting holes are provided on the back of the screen for more versatile arm- and wall-mounting options. This might be useful considering the ergonomics here are very limited.


Above: front and rear views of the stand and base. Click for larger versions

The oval shaped base is a glossy black plastic as well. Since the monitor arm attaches at the bottom of the screen on the back, it does mean the screen can be pretty wobbly with even a slight knock.


Above: full tilt adjustment range shown. Click for larger versions

The stand provides only a basic tilt adjustment as shown above. The range of the tilt is reasonable, although it's stiff to operate. Again, since the stand attaches at the bottom of the screen on the back, it's a bit unstable as you re-position the angle. Sadly the stand is very limited as there is no height, swivel or rotate adjustment offered here. When the screen is vertical, the bottom edge is ~65mm from the edge of the desk.

A summary of the screens ergonomic adjustments is shown below:

Function

Range

Smoothness

Ease of Use

Tilt

Yes

Smooth

Stiff

Height

n/a

-

-

Swivel

n/a

-

-

Rotate

n/a

-

-

Overall

Limited range of adjustments offered

The materials were of a moderate standard although the whole screen did feel a bit basic and low-cost if we're honest. Probably to be expected given the low retail cost. There was no audible noise from the screen, even when conducting specific tests which can often identify buzzing issues. The whole screen remained reasonably cool during prolonged use.


Above: interface connections on the back of the screen. Click for larger version

The back of the screen features all the connections. There is the power input (external brick needed), headphone out, audio in, Dual-link DVI, 2x HDMI and DisplayPort as shown.


Above: remote control provided

A remote control is provided with the screen which might be useful for those wanting to use it for external devices, Blu-ray players etc. Although much of the functionality is meaningless really as there aren't a whole lot of things you can control on the screen itself other than maybe the brightness and volume settings. The remote is also in Korean as you can see, although a paper diagram explaining what each button would do is provided in the box too in English.


 


OSD Menu


Above: OSD control buttons on the bottom edge of the screen. Click for larger version

The OSD menu is accessed and controlled through a series 6 pressable buttons located on the underside of the screen, in the bottom right hand corner. The above photo is taken from an angle below to show you the actual physical buttons, and you will see the labels are located on the front of the bezel. Finding the relevant button was a little tricky sometimes as it was not always obvious which one you were pressing, as the labels are quite a long way away from the buttons, which are  completely out of sight as well. To the right is the power on/off button as well.

Pressing the "S" button brings up a quick access selection of the video inputs.

The - and + buttons bring up quick access to the volume control for the integrated speakers.

The 'M' button gives you access to the main OSD menu, which is split in to 6 sections down the left hand side. The options available in each section are then shown on the right. The first section is the so-called "luminance" section, with options for brightness, contrast etc available. You can control gamma on/off here and the dynamic contrast ratio as well. You can also specify the source for the PiP options which is a little odd for the "luminance" section.

The second section is not shown in the pictures here as it seems to be related to controlling analogue input signals, which aren't actually available on this model. Must be a hangover from the OSD software from versions of the screen with a D-sub input. Instead, above is the third section for the 'color' menu. You can control a range of preset colour temperature modes here as well as enter a 'user' mode which then allows you to manually change the RGB levels listed.

The fourth section allows you to control the OSD menu software itself.

The fifth section allows you to change a few other features, most usefully the 'display size' which is the hardware aspect ratio control option. There are only options for full and 4:3 provided though.

The final sixth section gives you access to some settings related to the Picture In Picture and Picture By Picture options.

The menu itself was fairly easy to navigate although you do find you sometimes press the wrong button because of their location on the underside of the screen. There were a reasonable range of options to play with, although the screen is lacking any preset modes and control over the overdrive impulse which would have been useful.

 


Power Consumption

In terms of power consumption the we couldn't find any manufacturer specified figures. We carried out our normal tests to establish its power consumption ourselves.

State and Brightness Setting

Manufacturer Spec (W)

Measured Power Usage (W)

Default (50%)

-

39.5

Calibrated (50%)

-

39.5

Maximum Brightness (100%)

-

47.1

Minimum Brightness (0%)

-

29.2

Standby

-

5.6

We tested this ourselves and found that out of the box the screen used 39.5W at the default 50% brightness setting. In standby it used a comparatively high 5.6W, while most screens are <1W. Calibrated settings were a bit odd on this screen due to the way the brightness control operates. See the following sections of the review for more information. We have plotted these results below compared with other screens we have tested:



Panel and Backlighting

Panel Manufacturer

LG.Display

Colour Palette

16.7 million

Panel Technology

IPS

Colour Depth

8-bit

Panel Module

LM270WQ1-SLB1

Colour space

Standard gamut

Backlighting Type

W-LED

Colour space coverage (%)

82% NTSC, 80.4% Adobe RGB, 100% sRGB

Panel Part and Colour Depth

The screen features an LG.Display LM270WQ1-SLB1 IPS panel which is capable of producing 16.7 million colours. The panel offers an 8-bit colour depth and the part is confirmed when dismantling the screen as shown below.

 

Screen Coating

The screen coating is a light anti-glare (AG) offering. It isn't a semi-glossy coating, but it is light as seen on other modern IPS type panels. Thankfully it isn't a heavily grainy coating like some old IPS panels feature. It retains its anti-glare properties to avoid too many unwanted reflections of a full glossy coating, but does not produce an too grainy or dirty an image that some thicker AG coatings can. There were some slight cross-hatching patterns visible on the coating if you looked very closely.


Backlight Type and Colour Gamut

The screen uses a White-LED (W-LED) backlight unit which has become very popular in today's market. This helps reduce power consumption compared with older CCFL backlight units and brings about some environmental benefits as well. The W-LED unit offers a standard colour gamut which is approximately equal to the sRGB colour space. Studying the detailed panel spec sheet confirms colour space coverage of 82% NTSC, 80.4% Adobe RGB and 100% sRGB. Anyone wanting to work with wider colour spaces would need to consider wide gamut CCFL screens or the newer range of GB-r-LED type displays available now. If you want to read more about colour spaces and gamut then please have a read of our detailed article.


Backlight Dimming and Flicker

We tested the screen to establish the methods used to control backlight dimming. Our in depth article talks in more details about a common method used for this which is called Pulse Width Modulation (PWM). This in itself gives cause for concern to some users who have experienced eye strain, headaches and other symptoms as a result of the flickering backlight caused by this technology. We use a photosensor + oscilloscope system to measure backlight dimming control with a high level of accuracy and ease. These tests allow us to establish

1) Whether PWM is being used to control the backlight
2) The frequency and other characteristics at which this operates, if it is used
3) Whether a flicker may be introduced or potentially noticeable at certain settings

If PWM is used for backlight dimming, the higher the frequency, the less likely you are to see artefacts and flicker. The duty cycle (the time for which the backlight is on) is also important and the shorter the duty cycle, the more potential there is that you may see flicker. The other factor which can influence flicker is the amplitude of the PWM, measuring the difference in brightness output between the 'on' and 'off' states. Please remember that not every user would notice a flicker from a backlight using PWM, but it is something to be wary of. It is also a hard thing to quantify as it is very subjective when talking about whether a user may or may not experience the side effects.


100%                                                  50%                                                  0%


Above scale = 1 horizontal grid = 20ms

At 100% brightness a constant voltage is applied to the backlight. As you reduce the brightness setting to dim the backlight an oscillation is introduced operating at a frequency of 240Hz. This isn't a full amplitude on/off switching of the backlight as you see from some PWM methods, but there may still be some flickering introduced potentially to those who are sensitive to it.

Pulse Width Modulation Used

Yes, low amplitude oscillation

Cycling Frequency

240Hz

Possible Flicker at

 

100% Brightness

No

50% Brightness

Yes

0% Brightness

Yes

For an up to date list of all flicker-free (PWM free) monitors please see our Flicker Free Monitor Database.

 


Contrast Stability and Brightness

We wanted to see how much variance there was in the screens contrast as we adjusted the monitor setting for brightness. In theory, brightness and contrast are two independent parameters, and good contrast is a requirement regardless of the brightness adjustment. Unfortunately, such is not always the case in practice. We recorded the screens luminance and black depth at various OSD brightness settings, and calculated the contrast ratio from there. Graphics card settings were left at default with no ICC profile or calibration active. Tests were made using an X-rite i1 Display Pro colorimeter. It should be noted that we used the BasICColor calibration software here to record these, and so luminance at default settings may vary a little from the LaCie Blue Eye Pro report.

OSD Brightness

Luminance
(cd/m2)

Black Point (cd/m2)

Contrast Ratio
( x:1)

100

362.53

46.82

8

90

349.50

27.4

13

80

335.17

13.99

24

70

319.02

5.58

57

60

301.61

1.22

247

50

278.47

0.28

995

40

216.52

0.26

833

30

162.11

0.24

675

20

115.89

0.21

552

10

83.07

0.19

437

0

56.79

0.17

334

 

Total Luminance Adjustment Range (cd/m2)

305.74

Brightness OSD setting controls backlight?

Total Black Point Adjustment Range (cd/m2)

46.65

Average Static Contrast Ratio

-

PWM Free? 

Recommended OSD setting for 120 cd/m2

-

The brightness control behaved very oddly here. We've already established that the screen is not completely flicker free and that a 240Hz low amplitude oscillation is introduced for anything below 100% brightness. That would normally be a pretty good indication that PWM is being used for backlight dimming. If you observe the power consumption as you change the brightness setting you can see it is changing, suggesting the control is altering the backlight intensity to a degree.

However, it seems that this PWM method is also combined with a strange digital white level adjustment control. When you change the brightness setting you massively impact the contrast of the image. At the default 50% brightness setting the image looks as it should in terms of white vs. black balance and image quality. There is a decent 995:1 contrast ratio measured at this setting. However it is very bright, being measured at a high 278 cd/m2. If you increase the brightness setting the image becomes very washed out and pale and the contrast ratio drops hugely. Blacks become grey, to the point where at 100% brightness even though you've increased the luminance to 363 cd/m2, the image looks ridiculous. You wouldn't want to use the screen at anything above 50% brightness for sure.

More of a problem is that if you lower the brightness under 50% then the digital white level is again adjusted. Down to about 40% is just about ok, although the image quality is affected and contrast ratio crushed a little down to 833:1. Anything below that just looks bad, with contrast ratio taking a big hit to reach anywhere near a comfortable 120 cd/m2 type setting. At 40% brightness the luminance is a high 217 cd/m2 which is probably too much for normal working conditions for most people. Unfortunately it's impossible to get a more comfortable luminance level without crushing the contrast ratio and  messing up the picture appearance. Lowering the brightness via your graphics card settings will do the same thing as well. We really dislike these kind of brightness adjustments!

We have plotted the luminance trend on the graph above. The luminance output is reduced as you lower the brightness setting but the control is not only changing the backlight intensity to a degree, but also adjusting the digital white level as we've discussed above. Contrast ratio is ruined for pretty much any setting other than around the default 50% level.

You can see here that the contrast ratio is really crushed as you move away from the 50% brightness level. More so if you increase the brightness, not that you'd really ever want to as the screen is already too bright at the default 50% level.



Testing Methodology

An important thing to consider for most users is how a screen will perform out of the box and with some basic manual adjustments. Since most users won't have access to hardware colorimeter tools, it is important to understand how the screen is going to perform in terms of colour accuracy for the average user.

We restored our graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using an X-rite i1 Pro Spectrophotometer (not to be confused with the i1 Display Pro colorimeter) combined with LaCie's Blue Eye Pro software suite. An X-rite i1 Display Pro colorimeter was also used to verify the black point and contrast ratio since the i1 Pro spectrophotometer is less reliable at the darker end.


Targets for these tests are as follows:

  • CIE Diagram - validates the colour space covered by the monitors backlighting in a 2D view, with the black triangle representing the displays gamut, and other reference colour spaces shown for comparison

  • Gamma - we aim for 2.2 which is the default for computer monitors

  • Colour temperature / white point - we aim for 6500k which is the temperature of daylight

  • Luminance - we aim for 120 cd/m2, which is the recommended luminance for LCD monitors in normal lighting conditions

  • Black depth - we aim for as low as possible to maximise shadow detail and to offer us the best contrast ratio

  • Contrast ratio - we aim for as high as possible. Any dynamic contrast ratio controls are turned off here if present

  • dE average / maximum - as low as possible. If DeltaE >3, the color displayed is significantly different from the theoretical one, meaning that the difference will be perceptible to the viewer. If DeltaE <2, LaCie considers the calibration a success; there remains a slight difference, but it is barely undetectable. If DeltaE < 1, the color fidelity is excellent.



Default Performance and Setup

Default settings of the screen were as follows:

Monitor OSD Option

Default Settings

Brightness

50

Contrast

50

Colour Temp

7500k

RGB

n/a


Wasabi Mango QHD275 Universal - Default Settings

  

 

Default Settings

luminance (cd/m2)

305

Black Point (cd/m2)

0.31

Contrast Ratio

998:1

 

Initially out of the box the screen was set in the default 7500k colour temperature mode. Brightness was set at 50% by default and we've already established in the previous section of this review that it is the optimum setting. Anything higher or lower than this crushes contrast ratio significantly, since the brightness control is not a true backlight adjustment, and includes digital white level adjustments. The screen looked very bright out of the box, but apart from that the image quality looked pretty decent.

 

The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) is roughly equal to the sRGB colour space. There is some minor over-coverage in all shades, particularly blue, but not by anything significant. Default gamma was recorded at 2.3 average, leaving it with only a 4% deviance from the target which was good news. Especially in the absence of any decent gamma adjustment in the OSD menu. White point was measured at 6296k being a bit too warm from the target of 6500k but with a fairly low 3% deviance. Oddly this was nowhere near the specified 7500k setting listed in the OSD menu.

 

 

Luminance was recorded at a very bright 305 cd/m2 which is too high for prolonged general use. As we've already discussed it's impossible to bring this lower without impacting other areas of the setup, most notably contrast ratio. The black depth was 0.31 cd/m2 at this default brightness setting, giving us a decent static contrast ratio (for an IPS-type panel) of 998:1. Colour accuracy was mostly pretty good out of the box, with average dE at 2.7. Blue shades were a problem where dE ranged up to 9.5 maximum. When testing the screen with colour gradients there was some gradation evident as you will see from most monitors in darker tones, and some minor banding in places.


 

The OSD menu also offers a range of defined colour temperature modes, along with an 'sRGB' and 'user define' mode. We tested the sRGB mode and found that white point by default was even warmer at 5746k. The rest of the setup remained largely unchanged, with a slight drop in contrast ratio to 915:1. The 'user define' mode is more flexible and useful. This gives you access to the individual RGB levels which are set at 70 each by default. When switching to this mode you will observe a drop in luminance, down to around 162 cd/m2 by default. This is far more comfortable to use, but is a result of the reduced RGB levels, which in turn are basically reducing the digital white level. This does produce a lower luminance, but also massively crushes the contrast ratio (like lowering the main brightness control would) down to 564:1. This mode is handy for calibration, but by default should probably be avoided due to the crushed contrast ratio.

 

 

 

Calibration

 

We used the X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An X-rite i1 Display Pro colorimeter was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

 

Monitor OSD Option

Calibrated Settings

Brightness

50

Contrast

50

Colour Temp

User Define

RGB

94, 100, 100


Wasabi Mango QHD275 Universal  - Calibrated Settings

  
 

 

Calibrated Settings

luminance (cd/m2)

294

Black Point (cd/m2)

0.29

Contrast Ratio

1011:1

 

We changed to the 'user define' colour temperature mode which gave us access tot he RGB channels, allowing us to adjust the white point at the hardware level. These OSD changes allowed us to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level. We left the  LaCie software to calibrate to "max" brightness which would just retain the luminance of whatever brightness we'd set the screen to, and would not in any way try and alter the luminance at the graphics card level, which can reduce contrast ratio. These adjustments before profiling the screen would help preserve tonal values and limit banding issues. After this we let the software carry out the LUT adjustments and create an ICC profile.

 

Average gamma was now corrected to 2.2 average, correcting the 4% deviance we'd seen out of the box, but still leaving it with a minor 1% error. The white point was now also corrected to 6536k, leaving it 1% out from our target. Luminance was one are we could not improve without massively effecting the contrast ratio. In the absence of a proper backlight adjustment, you can either reduce brightness through the digital white level change (lower the 'brightness' setting in the OSD menu), or lower brightness from your graphics card. Either way, the image quality was negatively affected, crushing contrast ratio and making the image look bad. We had no choice really but to stick with the default 50% setting and live with a high luminance output of 294 cd/m2. This left us a black depth of 0.29 cd/m2 and maintained a very good static contrast ratio (for an IPS-type panel) of 1011:1. Colour accuracy of the resulting profile was excellent, with dE average of 0.6 and maximum of 1.1. LaCie would consider colour fidelity to be very good overall. Testing the screen with various colour gradients showed mostly smooth transitions. There was some slight gradation in darker tones and some minor banding introduced due to the adjustments to the graphics card LUT from the profilation of the screen. You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

 

 

 

Calibration Performance Comparisons


 

The comparisons made in this section try to give you a better view of how each screen performs, particularly out of the box which is what is going to matter to most consumers. When comparing the default factory settings for each monitor it is important to take into account several measurement areas - gamma, white point and colour accuracy. There's no point having a low dE colour accuracy figure if the gamma curve is way off for instance. A good factory calibration requires all 3 to be well set up. We have deliberately not included luminance in this comparison since this is normally far too high by default on every screen. However, that is very easily controlled through the brightness setting (on most screens) and should not impact the other areas being measured anyway. It is easy enough to obtain a suitable luminance for your working conditions and individual preferences, but a reliable factory setup in gamma, white point and colour accuracy is important and not as easy to change accurately without a calibration tool.

 

From these comparisons we can also compare the calibrated colour accuracy, black depth and contrast ratio. After a calibration the gamma, white point and luminance should all be at their desired targets.

 

 

Default setup of the screen out of the box was pretty good on the whole with gamma and white point being only a few % away from their targets. The contrast ratio was also strong at 998:1 for an IPS panel. Brightness was the main issue though as we've already talked about, being impossible to tame without messing up the image quality and contrast ratio.

 

 

 

The display was strong when it came to black depth and contrast ratio for an IPS-type panel. With a calibrated contrast ratio of 1011:1 it was comparable to some of the better screens using this kind of panel technology. It was not quite as high as some models like the recently tested Dell U2515H (1138:1) which holds the record for an IPS contrast ratio. Of course it can't compete with VA panel types which can reach over 2000:1 easily, and commonly up to 3000:1, even close to 5000:1 in some cases (not shown here on the graph). The issue with this screen is that this contrast ratio can only be achieved if you stick with the default 50% brightness and live with a very bright screen.

 


Viewing Angles


Above: Viewing angles shown from front and side, and  from above and below. Click for larger image

Viewing angles of the screen were very good as you would expect from an IPS-type panel. Horizontally there was very little colour tone shift until wide angles past about 45. A slight darkening of the image occurred horizontally from wider angles as you can see above as the contrast shifted slighting. Contrast shifts were more noticeable in the vertical field with the image appearing more pale, but overall they were very good. The screen offered the wide viewing angles of IPS technology and was free from the restrictive fields of view of TN Film panels, especially in the vertical plane. It was also free of the off-centre contrast shift you see from VA panels and a lot of the quite obvious gamma and colour tone shift you see from some of the modern VA panel type offerings. All as expected really from a modern IPS-type panel.


Above: View of an all black screen from the side. Click for larger version

On a black image there is a pale purple glow when viewed from an angle, commonly referred to as IPS-glow. This kind of glow is common on most IPS-type panels and can be distracting to some users. On older IPS panels (like the one used here) the glow is more purple in colour, whereas more modern IPS panels tend to be whiter. If you view dark content from a normal head-on viewing position, you can actually see this glow as your eyes look towards the edges of the screen if the screen is of a large size. This could be distracting if you work with a lot of dark content. The glow was normal here for an older IPS panel.



Panel Uniformity

We wanted to test here how uniform the brightness and colour temperature was across the screen, as well as identify any leakage from the backlight in dark lighting conditions. Measurements of the luminance were taken at 35 points across the panel on a pure white background. The measurements were taken using BasICColor's calibration software package, combined with an X-rite i1 Display Pro colorimeter. The below uniformity diagram shows the difference, as a percentage, between the measurement recorded at each point on the screen, as compared with the central reference point.

It is worth noting that panel uniformity can vary from one screen to another, and can depend on manufacturing lines, screen transport and other local factors. This is only a guide of the uniformity of the sample screen we have for review.
 


Uniformity of Luminance

The luminance uniformity of the screen was moderate with the sides showing some drop in luminance by about -22% in the most extreme cases. The left hand edge was darker than the central regions of the screen although not noticeably so in practice - largely because you need to run at a high luminance to maintain a decent contrast ratio on this model. Around 71% of the screen was within a 10% deviance of the central point which was not bad.


Backlight Leakage


Above: All black screen in a darkened room. Click for larger version

As usual we also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. The camera showed there was some clouding in the right hand corners where you could see more obvious lighter patches. There was also some bleed along the bottom edge, just left of the centre. Results may vary of course from unit to unit, but the bleed was a bit distracting here if you view the screen in a darkened room or view a  lot of darker content.

 


General and Office Applications

The QHD275 feature a large 2560 x 1440 WQHD resolution, a significant step up from the wide range of 1920 x 1080 screens on the market. The pixel pitch of 0.233 mm is quite small as a result, and by comparison a standard 16:10 format 24" model has a pixel pitch of 0.270mm and a 30" model has 0.250mm. These ultra-high resolution 27" models offer a tight pixel pitch and therefore small text as well. We found it quite a change originally coming from 21.5 - 24" sized screens back in the day, even those offering quite high resolutions and small pixel pitches. Although now we are very used to working with 27" 1440p screens all the time and find them very comfortable and a significant upgrade over 1080 / 1200p models. Some users may find the small text a little too small to read comfortably, and we'd advise caution if you are coming from a 19" or 22" screen for instance where the pixel pitch and text are much larger. The extra screen size takes some getting used to over a few days as there really is a lot of room to work with but once you do, it's excellent. For those wanting a high resolution for CAD, design, photo work etc, this is a really good option. The image was very sharp and crisp and text was very clear. With its WQHD display, you enjoy 77% more desktop space than a full HD screen to spread out your windows and palettes.

The light AG coating of the panel is certainly welcome, and much better than the grainy and 'dirty' appearance of older IPS AG coatings. The wide viewing angles provided by this panel technology on both horizontal and vertical planes, helps minimize on-screen colour shift when viewed from different angles. The default setup of the screen was pretty decent, offering a decent gamma curve, white point, contrast ratio and low dE. The main issue though as we've already discussed is the lack of a proper backlight adjustment. There is a low amplitude 240Hz PWM oscillation introduced as well so the screen cannot be classified as completely flicker free either. Since the brightness control adjusts the digital white level it is impossible to produce a decent, comfortable luminance for office type work without massively impacting picture quality and contrast. You will probably need to stick with the default 50% brightness setting for a good picture, but the luminance is then close to 300 cd/m2, making it uncomfortable for office work. There was no audible noise or buzzing from the screen, even when specifically looking for it using test images with a large amount of text at once. The screen also remains fairly cool even during prolonged use. There is no specific preset mode for office work or reading so you will need to have a general mode for all your uses really.

The screen doesn't have much in the way of extras, with no USB ports, card readers or ambient light sensors offered. There are some basic integrated 2x 2W stereo speakers which might be ok for the odd YouTube clip, but not up to much else. The stand is very limited in functionality as well with only a basic, stiff tilt adjustment offered and no height, swivel or rotate. The VESA mounting support may be useful to some people though to give more flexibility and the lack of ergonomic adjustments is one of the ways they've kept the cost down on this display.

 
Above: photo of text at 2560 x 1440 (top) and 1920 x 1080 (bottom)

The screen is designed to run at its native resolution of 2560 x 1440 and at a 60Hz recommended refresh rate. However, if you want you are able to run the screen outside of this resolution. We tested the screen at a lower 1920 x 1080 resolution to see how the screen handles the interpolation of the resolution, while maintaining the same aspect ratio of 16:9. At native resolution the text was very sharp and clear. When running at a 1080p resolution the text is still reasonably clear, with low levels of blurring. You do lose some screen real-estate as well of course but the image seems to be quite well interpolated from 1080p sources if needed.

 


Responsiveness and Gaming

Quoted G2G Response Time

6ms G2G

Quoted ISO Response Time

n/a

Panel Manufacturer and Technology

LG.Display

Panel Part

LM270WQ1-SLB1

Overdrive Used

Yes

Overdrive Control Available to User

No

Overdrive Settings

n/a

The QHD275 is rated by Wasabi Mango as having a 6ms G2G response time, which indicates the panel uses overdrive / response time compensation (RTC) technology to boost pixel transitions across grey to grey changes. There is no user control over the overdrive impulse within the OSD menu so we are reliant on the manufacturer setup. The part being used is the LG.Display LM270WQ1-SLB1 IPS panel. Have a read about response time in our specs section if you need additional information about response times and their measurement.

We will first test the screen using our thorough response time testing method. This uses an oscilloscope and photosensor to measure the pixel response times across a series of different transitions, in the full range from 0 (black) to 255 (white). This will give us a realistic view of how the monitor performs in real life, as opposed to being reliant only on a manufacturers spec. We can work out the response times for changing between many different shades, calculate the maximum, minimum and average grey to grey (G2G) response times, and provide an evaluation of any overshoot present on the monitor.

We use an ETC M526 oscilloscope for these measurements along with a custom photosensor device. Have a read of our response time measurement article for a full explanation of the testing methodology and reported data.

 

The average G2G response time was measured at 7.7ms which was very good for a 60Hz IPS-type panel overall. Some measurements reached as low as 4.6ms, meaning the screen does live up to its specified 6ms G2G figure in practice. Rise times were slightly faster than fall times and overall we were quite pleased as in the past we've seen fairly slow response times from a lot of Korean monitors.

Unfortunately the pretty low response times were not without some issue. Some fairly large amounts of overshoot were evident on the rise times, resulting in some pale trailing and artefacts on moving objects. It was not too catastrophic but the overshoot was certainly at a high level. A good 60Hz IPS-type panel can reach down to around 8.6ms G2G minimum most of the time without introducing any major overshoot, and so it seems the RTC had been pushed a little too far here. Response times had reached down to 7.7ms G2G, but some fairly high overshoot was introduced as a side-effect. You are not able to control the overdrive impulse either on this display so you have to live with their default setup.



Display Comparisons

The above comparison table and graph shows you the lowest, average and highest G2G response time measurement for each screen we have tested with our oscilloscope system. There is also a colour coded mark next to each screen in the table to indicate the RTC overshoot error, as the response time figure alone doesn't tell the whole story.

The measured response times of the QHD275 were good here, with a 7.7ms G2G average being faster than all the other 60Hz IPS-type panels shown. However, as we've already discussed it comes at the cost of some moderate levels of overshoot and the introduction of some pale halos in moving images. The new 144Hz capable IPS-type panels in the Asus MG279Q and Acer XB270HU are faster, reaching down to 5.5 - 6.5ms with little to no overshoot. Modern TN Film panels are faster than the QHD275 as well as you might expect, reaching down to 2.9 - 3.4ms G2G average on models like the Asus ROG Swift PG278Q and BenQ XL2730Z respectively, but again with moderate levels of overshoot introduced.

 

The screen was also tested using the chase test in PixPerAn for the following display comparisons. As a reminder, a series of pictures are taken on the highest shutter speed and compared, with the best case example shown on the left, and worst case example on the right. This should only be used as a rough guide to comparative responsiveness but is handy for a comparison between different screens and technologies as well as a means to compare those screens we tested before the introduction of our oscilloscope method.


27" 6ms G2G LG.Display IPS

In practice the QHD275 showed low levels of blurring in these tests, with the moving object looking quite sharp and clear. The colour transitions in this test didn't show any dark or pale overshoot, although we know from our oscilloscope tests that there is some there on certain transitions. Sadly with no control over the RTC impulse the overshoot could not be eliminated, although overall it was only at a moderate level.


27" 6ms G2G LG.Display IPS


27" 4ms G2G AU Optronics AHVA


27" 6.5ms G2G LG.Display H-IPS


27" 8ms G2G LG.Display AH-IPS (Response Time = Normal)


It is also interesting to compare the QHD275 to some of the other Korean models we have tested, along with the popular Dell U2715H. You can see that the QNIX and Achieva models show a far more noticeable trail behind the moving car, with high levels of blurring being evident. Their response times were measured at 13.2ms and 15.9ms G2G respectively, so are quite a lot slower than the Wasabi Mango display. Those other Korean screens didn't seem to use any overdrive at all, delivering slow response times from their IPS-type panels but without any overshoot at all. The gaming performance is certainly better on the Wasabi Mango with much faster pixel response times, even if you do need to live with some moderate overshoot sometimes. The popular Dell U2715H was a little slower than than Wasabi Mango (9.9ms G2G) but not by a massive amount, also showing lower levels of overshoot.
 


27" 6ms G2G LG.Display IPS


27" 4ms G2G AU Optronics AHVA (IPS-type) @ 144Hz (OD = Normal)


27" 1ms G2G AU Optronics TN Film @ 144Hz (OD = Normal)


27" 1ms G2G AU Optronics TN Film @ 144Hz (AMA = High)


23.5" 4ms G2G Sharp MVA + 120Hz

We've also included a comparison above against some other very fast 120Hz+ compatible screens we have tested. The screens shown here are all aimed primarily at gamers and have various features and extras which make them more suitable overall for gaming. Firstly there is a comparison against the excellent Acer XB270HU with very fast response times (5.5ms G2G, no overshoot), 144Hz refresh rate and also NVIDIA G-sync and Ultra Low Motion Blur (ULMB) support. That certainly delivers a much better gaming experience than the Wasabi Mango, probably to be expected given that's a gaming screen and a much higher retail price. It's currently our bench-mark for IPS panel gaming - well, actually our current favourite gaming screen of any type!

Then there's the very popular Asus ROG Swift PG278Q with its 144Hz refresh rate and fast response time TN Film panel. This showed very fast pixel response times (2.9ms G2G), with moderate levels of overshoot, but smooth movement thanks to its increased refresh rate. You are able to reduce the motion blur even more through the use of the ULMB strobed backlight as well if you need to and again this model also supports NVIDIA's G-sync technology.

Then there is a comparison against the BenQ XL2730Z with another very fast TN Film panel and 144Hz refresh rate. This showed very low levels of motion blur (3.4ms G2G), but some dark overshoot was introduced as a side-effect as you can see. This screen also includes a native Blur Reduction mode to help eliminate further perceived motion blur and works well, along with AMD FreeSync support.

Lastly there is the MVA based Eizo FG2421 screen with a fast response time (especially for the panel technology being used) and 120Hz refresh rate support. There is also an additional 'Turbo 240' motion blur reduction mode which really helps reduce the perceived motion blur in practice.
 


Additional Gaming Features

  • Aspect Ratio Control - The QHD275 has only two options in the menu for aspect ratio control. There are options for full and 4:3 only. There is no "aspect" option to maintain the source aspect at whatever it is, and no 1:1 pixel mapping option either. This isn't a major problem on this screen as if you're using a PC and want to run at a non-native resolution (for gaming etc) you can let the graphics card handle the scaling instead. Since the screen is a native 16:9 aspect ratio as well, if you are using an external device (games console, Blu-ray player) it should be ok since those generally run at 16:9 aspect themselves. You won't be able to 1:1 pixel map the common 1080p input, but it will at least not skew the aspect ratio. External inputs not from a PC of 16:10, 5:4 aspect ratios will be an issue though.
     

  • Preset Modes - There are no specific gaming preset modes available on this screen.



Lag

We have written an in depth article about input lag and the various measurement techniques which are used to evaluate this aspect of a display. It's important to first of all understand the different methods available and also what this lag means to you as an end-user.

Input Lag vs. Display Lag vs. Signal Processing

To avoid confusion with different terminology we will refer to this section of our reviews as just "lag" from now on, as there are a few different aspects to consider, and different interpretations of the term "input lag". We will consider the following points here as much as possible. The overall "display lag" is the first, that being the delay between the image being shown on the TFT display and that being shown on a CRT. This is what many people will know as input lag and originally was the measure made to explain why the image is a little behind when using a CRT. The older stopwatch based methods were the common way to measure this in the past, but through advanced studies have been shown to be quite inaccurate. As a result, more advanced tools like SMTT provide a method to measure that delay between a TFT and CRT while removing the inaccuracies of older stopwatch methods.

In reality that lag / delay is caused by a combination of two things - the signal processing delay caused by the TFT electronics / scaler, and the response time of the pixels themselves. Most "input lag" measurements over the years have always been based on the overall display lag (signal processing + response time) and indeed the SMTT tool is based on this visual difference between a CRT and TFT and so measures the overall display lag. In practice the signal processing is the element which gives the feel of lag to the user, and the response time of course can impact blurring, and overall image quality in moving scenes. As people become more aware of lag as a possible issue, we are of course keen to try and understand the split between the two as much as possible to give a complete picture.

The signal processing element within that is quite hard to identify without extremely high end equipment and very complicated methods. In fact the studies by Thomas Thiemann which really kicked this whole thing off were based on equipment worth >100,1000 Euro, requiring extremely high bandwidths and very complicated methods to trigger the correct behaviour and accurately measure the signal processing on its own. Other techniques which are being used since are not conducted by Thomas (he is a freelance writer) or based on this equipment or technique, and may also be subject to other errors or inaccuracies based on our conversations with him since. It's very hard as a result to produce a technique which will measure just the signal processing on its own unfortunately. Many measurement techniques are also not explained and so it is important to try and get a picture from various sources if possible to make an informed judgement about a display overall.

For our tests we will continue to use the SMTT tool to measure the overall "display lag". From there we can use our oscilloscope system to measure the response time across a wide range of grey to grey (G2G) transitions as recorded in our response time tests. Since SMTT will not include the full response time within its measurements, after speaking with Thomas further about the situation we will subtract half of the average G2G response time from the total display lag. This should allow us to give a good estimation of how much of the overall lag is attributable to the signal processing element on its own.

 

Lag Classification


To help in this section we will also introduce a broader classification system for these results to help categorise each screen as one of the following levels:

  • Class 1) Less than 16ms / 1 frame lag at 60Hz - should be fine for gamers, even at high levels

  • Class 2) A lag of 16 - 32ms / One to two frames of lag at 60Hz - moderate lag but should be fine for many gamers. Caution advised for serious gaming and FPS

  • Class 3) A lag of more than 32ms / more than 2 frames of lag at 60Hz - Some noticeable lag in daily usage, not suitable for high end gaming

For the full reviews of the models compared here and the dates they were written (and when screens were approximately released to the market), please see our full reviews index.

(Measurements in ms)

Standard Mode

Total Display Lag (SMTT 2)

28.80

Pixel Response Time Element

3.85

Estimated Signal Processing Lag

24.95

Lag Classification

2

 

 Class 2

We have provided a comparison above against other models we have tested to give an indication between screens. The screens tested are split into two measurements which are based on our overall display lag tests (using SMTT) and half the average G2G response time, as measured by the oscilloscope. The response time is split from the overall display lag and shown on the graph as the green bar. From there, the signal processing (red bar) can be provided as a good estimation.

The QHD275 showed a total display lag of 28.8ms. 3.85ms of this can be accounted for by pixel response times roughly, leaving us with approximately 24.95ms of signal processing lag. This is basically 1.5 frames at 60Hz refresh rate and fairly standard for displays with a scaler and multi-inputs like this. It could be a bit too high for people wanting to play FPS or competitive gaming.




Movies and Video

The following summarises the screens performance in video applications:

  • 27" screen size makes it a reasonable option for an all-in-one multimedia screen, much smaller than LCD TV's and many larger format desktop monitors which are now emerging.

  • 16:9 aspect ratio is well suited to videos and movies, leaving you with smaller/no borders on DVD's and wide screen content at the top and bottom than on a 16:10 aspect display.

  • 2560 x 1440 resolution can support full 1080 HD resolution content.

  • Digital interfaces support HDCP for any encrypted and protected content

  • Good range of interface options available here.

  • Cable provided in the box for Dual-link DVI only, no HDMI or DisplayPort cables provided.

  • Light AG coating provides clear images with no major graininess, and without the unwanted reflections of a glossy solution.

  • Contrast ratio is the problem as it varies massively across the brightness adjustment range. The brightness control changes the digital white level as well as (to a degree) the backlight intensity, and so you massively crush contrast ratio when you alter away from a high setting of around 50%. As a result, running the screen at a more comfortable lower luminance results in a significantly reduced contrast ratio and a loss of a huge amount of detail in the darker tonal range. This is not a good option for movie viewing as a result.

  • Black depth and contrast ratio are very good for an IPS-type panel at 1011:1 after calibration. Detail in darker scenes should not be lost as a result as long as you can live with the default 50% brightness setting and resulting high luminance.

  • No specific preset modes offered for movies or any other uses.

  • Very good pixel responsiveness which can handle fast moving scenes in movies without issue. Some moderate overshoot issues on some transitions which could result in some pale trailing. No option to turn the overdrive down/off sadly.

  • Wide viewing angles from IPS panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles. Pale purple glow from an angle on black content may be problematic to some users and is common for IPS panel technology.

  • Some backlight leakage on our sample but results may vary.

  • Very limited range of ergonomic adjustments available from the stand, with only tilt available. Lacking any other adjustments making it potentially a problem for moving your viewing position.

  • Basic 2x 2W integrated stereo speakers offered on this model along with a headphone connection. Might be ok for the odd video clip but not a full movie.

  • Hardware aspect ratio control provided with options for full and 4:3 only. Missing an "auto aspect" and 1:1 pixel mapping which may be problematic for some external devices depending on their source aspect ratio.

  • Picture By Picture (PbP) or Picture In Picture (PiP) are available on this model if you want to use them.

     


Conclusion

We have mixed feelings about the Wasabi Mango QHD275 Universal. On the positive side the screen delivers a decent IPS panel with 2560 x 1440 at a very low retail price. That's one of the key aims here for Korean manufacturers like Wasabi Mango, allowing this screen to be priced at ~220 GBP, whereas mainstream competitors like the Dell U2715H are ~390 GBP. The panel delivers a high resolution, pretty decent default setup and the wide viewing angles offered from this technology. We were pleased with the wide range of inputs offered, considering those are normally one of the first things to go when cutting cost. Pixel response times impressed us as well, whereas we've seen very slow Korean panels in the past this one was overdriven nicely. Maybe a little too far given the moderate overshoot but still a better result than other manufacturers we've seen in the past.

Unfortunately we cannot overlook the very disappointing brightness control, adjusting the digital white levels and causing real problems for anything other than the default luminance. That's unforgivable for any display we feel, although frustratingly common on Korean displays it seems. Obviously the low retail cost can also be seen in some areas, with a very basic stand being one area where costs have been clearly trimmed. Build quality and design are also a bit budget but to be expected we suppose.

If you appreciate the review and enjoy reading and like our work, we would welcome a donation to the site to help us continue to make quality and detailed reviews for you.
 

Pros

Cons

Low cost IPS display with 2560 x 1440 resolution

Brightness control does not control backlight properly, creating a lot of problems

Decent response times

Limited ergonomic adjustments from the stand due to cost cutting

Good range of connectivity options

Fairly high lag

 

 

Back to Top

 

Sections
______
 

Reviews

Articles

News

Forum

Buying Support

___________

 

TFT Selector

Specifications Explained

Terms and Functions

Technologies

Frequently Asked Questions

Resources

_______

 

Panel Search Tool
Settings and ICC Profiles Database

Monitor Panel Parts Database

Laptop Panel Parts Database

Links

About

_____

 

Contact

Donations

Store

Advertise

 


    Copyright, TFT Central.                 Privacy Policy and Cookies

 

     Search TFT Central