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Introduction

Over the last year or so there has been a growing interest in low-cost monitors being manufactured in Korea and distributed Worldwide, primarily by sellers on eBay. These screens have captured the interest of buyers since they are generally high resolution models (27 and 30"), using quality IPS panels as used in popular models from the likes of Dell and Apple, and importantly, are available at very low costs. We talked about these Korean screens a little, back in March 2012 but have not really had chance to look at them in much more detail since. While they have been discussed a lot online and snapped up by many buyers looking for a bargain, there have always been big question marks around their quality and warranty. Shipping these models internationally via eBay has been a little worrying for many people, and with doubts around the after-sales support and returns policy, many people have just been put off.

Some local alternatives have emerged since, helping to offer people other low cost screens but with the safety net of a local distributor and support/warranty structure. In the UK, models like the DGM IPS-2701WPH have emerged to offer a low cost alternative to the mainstream offerings from Dell, HP, Apple, NEC and the likes. While these have no doubt been a lower end display choice, with a more basic set of features and specs, they have still interested many buyers looking for a bargain. Despite the availability of these local alternatives, the Korean models have remained popular.

Now UK-based IT supplier www.pcbuyit.co.uk have started to supply some of the Korean models themselves, backed by a proper warranty and support service as well. So far, models from Achieva Shimian are starting to emerge through PCBuyIT and we have already reviewed the 30" Achieva Shimian QH300-IPSMS. We now also have the new Achieva Shimian 27" IPS Zero-G monitor with us for review. This is also available in some locations re-branded as the Monoprice 27" IPS Zero-G. In fact the Achieva box even mentions Monoprice, but basically it's the same monitor just supplied under a different name by different suppliers.

Specifications and Features

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

The Achieva Shimian 27" IPS Zero-G offers a limited set of connectivity options. There are only Dual-link DVI-D and D-sub (VGA) provided for video interfaces, and the screen is lacking modern connections like HDMI or DisplayPort, presumably as a cost saving exercise. The DVI connection should be used where possible, but we did find that the VGA connection even supported the full native 2560 x 1440 resolution which was unusual. The digital interface is HDCP certified for encrypted content as well.

The screen comes packaged with a dual-link DVI and audio cables which is useful although there is no VGA cable provided with the screen unfortunately, although probably not really needed by most. The screen has an external power supply which is provided as well. There are no further features such as USB ports, speakers, audio connections, card readers of light sensors on this model so it is limited in terms of special features.

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

OSD Menu

Above: views of OSD operational buttons on the back edge of the screen

Power Consumption

In terms of power consumption the manufacturer lists <90W during operation and <1.5W in standby. We carried out our normal tests to establish its power consumption ourselves.

We tested this ourselves and found that out of the box the screen used a pretty high 63.4W of power while at its default brightness setting of 75%. At the maximum brightness level the screen used 64.1W of power, and at the lowest setting this was measured at 58.8W. Once calibrated we had reached a power consumption of 58.8W which had been once the screen had been set to achieve a luminance of 120 cd/m². During standby the screen uses 0.5W of power. We have plotted the results of these measurements on the graph below. You may note from these measurements that there isn't really much difference in the power consumption between the maximum and minimum brightness settings, and that the calibrated power consumption is pretty high for a W-LED backlight unit. There is a reason for this which we will discuss later on in the review:

Panel and Backlighting

Panel and Colour Depth

The Achieva Shimian 27" IPS Zero-G sample we tested utilises an LG.Display LM270WQ1-SDF1 H-IPS panel which is capable of producing 1.07 billion colours. According to the detailed panel spec sheet this is done with an 8-bit colour depth and an additional Frame Rate Control (FRC) stage. The panel offers support for 10-bit content. This gives a colour depth support for 1.07 billion colours. However,  you need to take into account whether this is practically useable and whether you're ever going to truly use that colour depth. You need to have a full 10-bit end to end workflow to take advantage of it which is still quite expensive to achieve and rare in the market, certainly for your average user. This includes relevant applications and graphics cards as well, so to many people this 10-bit support might be irrelevant.
 

Panel Coating

The screen coating on the 27" IPS Zero-G is glossy, producing a crisp and clean image and making the colours and blacks "pop" somewhat to the user. Being glossy though, it does produce a fair amount of reflections, although not as severe as some glass-fronted screens we have tested like the Dell S2740L for instance. Some users prefer glossy screen coatings, but it really does depend on preference. A key thing to consider is the positioning of the screen with windows and light sources, as the reflective nature could prove problematic in some cases. Achieva actually talk about having a  lower reflectivity of the panel surface since they have used "plasma deposition coating technology" apparently.

The glossy coating also extends to cover the sides of the screen, right up to the edge pretty much, and so you do have a completely glossy front to contend with. This can also be a bit of a pain with dust and finger prints, so keep a cleaning cloth handy.
 

Backlight 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 (equating to ~77% NTSC). Studying the detailed panel spec sheet confirms a colour space coverage of 99.9% sRGB, 77% NTSC and 77.6% Adobe RGB. Anyone wanting to work with wider colour spaces would need to consider wide gamut CCFL screens, or perhaps the new range of GB-LED displays.
 

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 symptons as a result of the flickering backlight caused by this technology. Previously we have used a camera based method as described in the article to capture results at brightness settings of 100, 50 and 0. We now have a more advanced photosensor +  oscilloscope system which will allow us to measure backlight dimming control with more accuracy and ultimately more 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%

Above scale = 1 horizontal grid = 20ms

            0%
 
Above scale = 1 horizontal grid = 20ms

At all the brightness settings a constant voltage was applied to the backlight and it remained continually lit. PWM was not being used for backlight dimming. This might sound a positive thing, and from a flickering point of view on the face of it, it is. However, rather than the backlight being controlled by a Direct Current (DC), it is actually constantly lit at the same voltage, no matter what brightness setting you choose in the OSD menu. Instead, as you lower the brightness control you are instead altering the digital white level, reducing the brightness output to the user, but without actually changing the backlight intensity. This is quite an odd way to control the screen brightness and very rarely used (although we have seen the same from other Korean models we have tested in our lab). Since the backlight intensity is not being changed, the power consumption remains pretty much static throughout the brightness range, meaning you are always using the maximum power for the screen. More worrying is that as you lower the brightness setting, the contrast ratio gets crushed very badly. We will look at this a bit more later on in the review, but this is not a good way to regulate brightness for a monitor and was a shame.

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

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.

I restored my graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed 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:

Achieva Shimian 27" IPS Zero-G - Default Factory Settings

 

 

Out of the box the screen looked pretty good to the naked eye, apart from the fact it was too bright for prolonged use. The picture looked crisp, clear and sharp and the colour balance felt good. The contrast between black and white also appeared good and the glossy coating made the colours and blacks "pop" somewhat. We went ahead and measured the default state with the i1 Pro.

The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) matches the sRGB colour space pretty well, with some over-coverage evident in blue shades. Default gamma was recorded at 2.3 average, leaving it a little out with a 2% deviance from the target of 2.2 which wasn't too bad. White point was a little too warm, being measured at 6149k and leaving it a small 5% out from our target of 6500k. Note that we are using a spectrophotometer to make these measurements which is not sensitive to the wide gamut backlight as some colorimeter devices can be. When using a standard gamut colorimeter not designed to work with modern backlighting units like W-LED, WCG-CCFL and GB-LED there can be a typical deviance of 300 - 600k in the white point measurement which is why some sources may refer to a different white point in this test incorrectly.

Luminance was recorded at a bright 285 cd/m² which is far too high for prolonged general use. The screen was set at a default 75% brightness in the OSD menu but that is easy to change of course to reach a more comfortable setting, although as you will see in the following sections, it isn't without a cost! The black depth was 0.34 cd/m² at this default brightness setting, giving us a very good (for an IPS panel) static contrast ratio of 848:1. Colour accuracy was very good as well out of the box with a default dE of only 1.7, and maximum of 3.8. Testing the screen with various gradients showed smooth transitions with no sign of any banding thankfully. There was some moderate levels of gradation evident in darker tones as you will see from most monitors.

Colour Temperatures

The 27" IPS Zero-G features a range of colour temperature presets within the OSD 'color' menu as shown above. There are options as shown in the table below, designed to target specific defined white points. We measured the screen with the X-rite i1 Pro spectrophotometer in each of the preset modes to establish their colour temperature / white point out of the box. All other settings were left at factory defaults and no ICC profile was active. The results are recorded below:

The warmest 5000k mode was too cool, being  598k too high with a 12% deviance. We had already seen that the default 6500k mode was a little too warm, with a 5.2% deviance in these measurements and being measured at 6163k. In fact the supposed 7500k and 8200k modes got us nearer to the 6500k target. Obviously these were then a long way out from their desired white point, but were at least closer to the 6500k we were after. Using the 8200k preset mode actually returned a white point of 6451k, being very close to the 6500k target we use for our reviews. The 9300k mode was only measured at 6833k, and the 11,500k mode at 7087k, so that's the coolest you can get to via the OSD settings. These presets were obviously quite a long way out from their targets. The user define mode allows you to control the RGB channels individually as well so we will use that for our calibration process.

Contrast Stability and Brightness

There were some problems with the brightness control of this screen which we will talk about in more detail in a moment. First of all the luminance range of the screen was good on the whole. At the maximum brightness setting the screen reached 343.18 cd/m² which is more than enough for most users we're sure but a fair bit lower than the specified 400 cd/m² maximum. At the lower end of the adjustment range you could reach down to 153.97 cd/m². This is probably not dark enough for most people and the recommended luminance for an LCD screen in normal lighting conditions is 120 cd/m². This minimum brightness adjustment didn't seem sufficient. It was possible to get a lower luminance from the screen if you switch from the default 6500k colour temp preset to the 'user define' mode. This seemed to adjust the digital white level further (a result of the RGB channels having been adjusted), and at the lowest 0% brightness setting you could reach down now as low as 76.35 cd/m². This should be sufficient for most users, even if working in darkened room conditions.

We have plotted the luminance trend on the graph above. The screen behaves as it should in this regard, with a reduction in the luminance output of the screen controlled by the reduction in the OSD brightness setting in a pretty linear relationship. As we discussed earlier, the backlight dimming is achieved without the use of PWM and so those prone to any issues with backlight flickering need not worry here. However, all is now quite what it seems unfortunately.

While the screen doesn't use PWM for backlight dimming (great for those who worry about flicker), the brightness adjustment isn't actually controlling the backlight here. Instead, as you change the brightness control you are changing the digital white level. The result? A severely crushed contrast ratio as you change the brightness setting away from the default factory optimised level. At the default 75% brightness setting we had measured a luminance of 285 cd/m², and a resulting contrast ratio of 848:1. That in itself is very good for an IPS panel, but the screen is far too bright to use comfortably. The problem is that as you lower the brightness control, you reduce the luminance output of the screen, but reduce your contrast ratio at the same time. The contrast ratio drops down to only 497:1 when at the 0% brightness setting (in the default 6500k mode). If you revert to the 'user define' mode you can reduce your luminance down to ~76 cd/m², but the contrast ratio is a measly 243:1. Again in this mode further digital white level adjustments have been made to give you a darker display, but the contrast ratio is awful.

This is a very rare thing to see in the modern desktop monitor market, and frankly is very disappointing. The brightness control should be controlling the backlight intensity, allowing you to achieve a good range of luminance while maintaining a stable contrast ratio as well. As a result the only way to get a more comfortable brightness from the display is to change the monitors digital white level, or change your graphics card brightness output. Either way, you are crushing the contrast ratio significantly.

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.

Achieva Shimian 27" IPS Zero-G - Calibrated Settings

   

We knew we were going to have some problems with the calibration since it was not possible to reach a comfortable luminance of ~120 cd/m² without severely impacting contrast ratio. We adjusted the brightness control down as low as we could, but the profilation would also make further adjustments at the graphics card level, again at the cost of contrast. We reverted to the 'user define' preset mode in the OSD menu to allow us access to the individual RGB channels, bumping them all up to 100 to start with. Adjustments were made during the process to the RGB channels as shown in the table above. This allowed us to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level. This 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 had been corrected to 2.2 average according to the initial test, correcting some of the default 2% deviance we'd found out of the box, but leaving us with a slight 1% deviance overall. The white point was also corrected to 6526k, correcting the slightly warm we had observed before (6149k default). Luminance had also been improved thanks to the adjustment to the brightness control, and through the graphics card adjustments and was now being measured at 121 cd/m². Unfortunately these digital white level adjustments had resulted in a very poor contrast ratio of only 397:1 which was a shame, but unavoidable. Colour accuracy had been corrected nicely, with dE average of 0.5 and maximum of 1.1. LaCie would consider colour fidelity to be excellent.

Testing the screen with various colour gradients showed mostly smooth transitions. There was some slight gradation in darker tones and some banding introduced in dark and mid tones 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 27" IPS Zero-G was  very good on the most part to be fair. Gamma and white point were very close to their targets, with the latter being only a little too warm. In fact you could improve things by switching to the 8200k preset mode in the OSD menu which actually took you very close to the desired 6500k white point. Colour accuracy was very good as well with a decent factory calibration resulting in an average dE of only 1.7. Contrast ratio was also very good for an IPS panel out of the box at 848:1. The only area which was not great was the luminance, and with a 285 cd/m² default , that was really the main thing which needed to be corrected. Normally that would be fine, and we'd recommend a simple adjustment to the brightness control to turn the backlight down to whatever level you feel comfortable. However, as we've already discussed, this drastically impacted contrast ratio as there was no true backlight control available.

The calibrated black depth and contrast ratio were the problem with this screen. With no backlight control, the digital white adjustments crushed contrast ratio significantly when trying to reach a comfortable target luminance. A resulting 397:1 contrast ratio was very poor unfortunately.

Viewing Angles

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

Viewing angles of the 27" IPS Zero-G were very good as you would expect from an IPS 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 slightly more noticeable in the vertical field 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 AMVA and PVA offerings. All as expected really from a modern IPS panel.

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

On a black image there was a noticeable white glow which can be problematic on some IPS panels. If you are working in darkened room conditions and with dark content on the screen this may prove difficult. As you change your line of sight the white, silvery glow appears across the panel. This may be more pronounced on a model this size as often your line of sight means the corners of the screen are at an angle to you. There is no A-TW polarizer on this panel which is rarely used now in the market but was implemented on some older screens to improve the off centre black viewing.

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 and colour temperature were taken at 35 points across the panel on a pure white background. The measurements for luminance were taken using BasICColor's calibration software package, combined with an X-rite i1 Display Pro colorimeter with a central point on the screen calibrated to 120 cd/m². Measurements for colour temperature (white point) were taken using BasICColor software and the i1 Pro spectrophotometer which can more accurately measure the white point of different backlighting technologies. 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 pretty good overall. There were some small deviances in the lower left hand region where the luminance dropped down to 113 cd/m² minimum, and in the lower right hand region where it was a bit brighter at 128 cd/m². Overall there was only a small deviance of ~5% across most the screen, compared with a central point which was good. Around 90% of the screen was within only a 5% deviance from the central point which was very good.
 

Uniformity of White Point / Colour Temperature

The colour temperature uniformity was measured based on a centrally calibrated 6500k point. As you can see, the colour temperature was very uniform across the panel with only small deviations across the screen. There was a maximum of 5.06% deviance between any two points on the screen. The upper central region seemed to be a little cooler than the other areas of the screen where it was closer to 6500k.

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. There was no major backlight bleeding to the naked eye and the uniformity looked pretty good, even in a darkened room. The camera captured some slight clouding from the bottom left and top right hand corners, but not something which you should notice in practice.

General and Office Applications

The 27" IPS Zero-G feature a massive 2560 x 1440 WQHD resolution which is only just a little bit less vertically than a 30" screen. The pixel pitch of 0.231mm is very 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 the tightest pixel pitch and therefore the smallest text as well. We found it quite a change coming from 21.5 - 24" sized screens, even those offering quite high resolutions and small pixel pitches.  Some users may find the small text a little too small to read comfortably, and I'd advise caution if you are coming from a 19" or 22" screen for instance where the pixel pitch and text are much larger. I found a 30" screen to be quite a change with text size when I first used one, and this is very similar and even a little bit smaller! The extra screen size also takes some getting used to over a few days as there really is a lot of room to work with.

The glossy screen coating is not to everyone's taste but does provide a nice crisp and clean image certainly. The glossy coating can make the colours and blacks "pop" and a lot of people prefer this type of coating on their monitor. There is the issue of reflections which may impact some office work, so you need to ensure the screen is well positioned relative to windows and lamps. The screen coating can also pick up a lot of dust and fingerprints so keep a cloth near by.

The wide viewing angles provided by the IPS 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 good really in terms of gamma, white point and colour accuracy, but unfortunately the screen was far too bright. You are able to achieve a lower luminance from the screen, but it comes at the cost of contrast ratio which we've already discussed at length. That could be a major problem to some users and you can't really avoid it with the current screen. I suppose at least with this odd brightness control the screen at the moment does not use Pulse-Width modulation (PWM) to control backlight dimming and so those who suffer from eye fatigue or headaches associated with flickering backlights need not worry keep this in mind. There is some feint high pitch buzzing from the screen in certain conditions, mainly when specifically looking for it using test images with a large amount of text at once. In normal day to day uses, we didn't notice any issue.

The screen offers no extras unfortunately such as USB ports or card readers which can be useful in office environments. There was also only a limited range of ergonomic adjustments available from the stand with only a tilt adjustment. The VESA mounting support may also be useful to some people though.

 
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 as you can see from the top photograph. When you switch to a lower resolution the text is larger of course but still very clear. The screen seems to interpolate the image well.

Responsiveness and Gaming

The 27" IPS Zero-G is rated by Achieva as having a 6.5 ms G2G response time which implies the use of overdrive / response time compensation (RTC) technology, used to boost pixel transitions across grey to grey changes. There is no user control over the overdrive impulse within the OSD menu and so we are reliant on the factory setup. The part being used is the LG.Display LM270WQ1-SDF1 H-IPS panel. Have a read about response time in our specs section if you need additional information about this 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 20 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 actual real life performance of the screen didn't live up to the specification at all unfortunately. The specified 6.5 ms G2G response time was really only the best case example from any of the measured transitions, and the only transitions which could live up to this spec were those changes from grey shades to black (x - 0). Overall the rise times shown in the upper right portion of the table (changes from darker to lighter shades) were much slower, with an average of 19.8ms. Some of the fall times in the bottom left hand part of the table (changes from lighter to darker shades) were a bit faster, with an average of 12ms, but the changes to the lighter end were slower up to ~18ms. The average G2G response time across the matrix was 15.9ms, making it pretty slow really.

As we begin to measure more screens with the oscilloscope system we can begin to plot them on a graph like the above for easy comparison. This shows you the lowest, average and highest G2G response time measurement for each screen. As you can see, the Achieva 27" IPS Zero-G performed quite slowly compared with all the other models tested here. It was quite a bit slower than the Achieva QH300-IPSMS (8.7ms G2G average) as well.

If we evaluate the Response Time Compensation (RTC) overshoot then the results are pleasing and there is no overshoot evident on the screen at all. The overdrive impulse is modest enough (non existent?) that it does not push the pixel transitions too far, and so there are no issues. A good result from this point of view, but the RTC impulse should probably have been more aggressive to help boost the pretty slow response times we think.

Transition: 50-150-50
(scale = 20ms)

The above oscillogram is a classic example of what we saw. This is from the transition from 50-150-50 as an example. The rise times are slow (19.5ms), the fall times are a bit faster (10.6ms), and there is no overshoot on either the rise or fall time.

Display Comparisons

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" 6.5ms G2G LG.Display H-IPS

In practice the Achieva 27" IPS Zero-G showed fairly moderate levels of motion blur which was detectable to the naked eye and picked up in these tests. There was nothing too severe although it didn't feel as fast as other panels we have tested. There was thankfully no overshoot detectable, and we've already confirmed with our oscilloscope system that this screen is free from such issues thankfully.

27" 6.5ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

27" 8ms G2G LG.Display AH-IPS

27" 5ms G2G Samsung PLS (Trace Free = 40)

27" 12ms G2G Samsung PLS (Response Time = Advanced)

We have also provided a comparison of the 27" IPS Zero-G above against 4 other 27" high res screens we have tested. The DGM IPS-2701WPH is a similarly low cost offering with a glossy coating and the same LM270WQ1 panel (albeit a different revision). This showed similar levels of blur to the Achieva which is probably expected, perhaps being a little faster in practice. The very popular Dell U2713HM was quite a bit faster with improved response times and a clearer moving image as a result. There was no overshoot still on this model which was pleasing. The Asus PB278Q and ViewSonic VP2770-LED both feature PLS panels from Samsung, very similar overall to IPS but a competing technology. Both were faster than the Achieva in these tests, offering less blurring. In the case of the Asus there was a small amount of overshoot introduced, but not much at all while at the modest Trace Free setting of 40.

27" 6.5ms G2G LG.Display H-IPS

27"WS 4ms G2G AU Optronics AMVA (AMA = High)

27" 7ms G2G LG.Display AH-IPS

We can also compare the screen against a couple of the other popular 27" models we've tested, this time offering a smaller 1920 x 1080 resolution. The BenQ GW2760HS performed quite similarly in practice to the Achieva here, not being particularly fast really but not too bad. In the AMA 'High' setting it was at least free from any obvious overshoot problems. The Dell S2740L was a little faster than the other two screens, with less blurring of the moving image. However a dark overshoot artefact was introduced which you can clearly see in the images. A sign that the RTC impulse was too aggressive.

27" 6.5ms G2G LG.Display H-IPS

27" 2ms G2G Chi Mei Innolux TN Film +144Hz (Trace Free = 60)

24" 2ms G2G AU Optronics TN Film + 120Hz (AMA = On)

27" 1ms G2G Chi Mei Innolux TN Film + 120Hz (Over Drive = 0)

22" 3ms G2G Samsung TN Film + 120Hz

We've also included a comparison above against four very fast 120Hz+ compatible screens we have tested. In all cases these other screens are using TN Film panels and are aimed primarily at gamers. Firstly there is a comparison against the Asus VG278HE with its 144Hz refresh rate. This showed very fast pixel response times and smooth movement thanks to its increased refresh rate. You are able to reduce the motion blur even more through the use of the LightBoost strobed backlight which we talked about in depth in our article about Motion Blur Reduction Backlights.

Then there is a comparison against the BenQ XL2420T. This showed very low levels of motion blur, but some dark overshoot was introduced as a side-effect. The Iiyama G2773HS was very responsive and even has a quoted 1ms G2G response time. This showed very low levels of blur and had minimal issue with overshoot. The Samsung SM2233RZ performed very well in these tests and showed very low levels of motion blur also. When 120Hz mode was enabled the overdrive artefacts evident in 60Hz mode were almost completely eliminated, which is something we have seen with the BenQ XL2420T as well.

While these pixel response tests show the Achieve to have moderate pixel transitions and freedom from any overshoot at least, there is something else going on as well here which can't be picked out by the camera. All of these other TN Film models are running at 120Hz (or higher) refresh rates, which allows for improved 120fps+ frame rates and the support of 3D stereoscopic content as well. This can really help improve smoothness and the overall gaming experience so these screens still have the edge when it comes to fast gaming.

The responsiveness of the 27" IPS Zero-G was moderate really. It didn't live up to its 6.5ms G2G spec really in practice, and the average response time was much slower at 15.9ms. The rise times were the main problem, where the transitions took quite a long time (19.8ms average). The RTC impulse was very tame here which resulted in these fairly slow response times. At least it did mean the screen was free from any overshoot problems at all which is certainly a positive. In practice it didn't feel as fast as some popular models we'd tested like the U2713HM for instance. It should still be adequate for some moderate gaming, but those wanting to play fast FPS or competitive games may want to consider some of the more gamer orientated 120Hz+ compatible displays out there. Even better still would be models equipped with LightBoost systems for optimum motion blur elimination.

Additional Gaming Features
 

Aspect Ratio Control - The screen offers only two options for aspect ratio control. These aren't listed in the OSD menu, but you can control them using the down arrow button as a quick access. There are only options to fill the screen, or to force 4:3 aspect ratios. These options are a little limited and there's no way to maintain a 16:10, 5:4 or 1:1 pixel mapping via the hardware. This probably isn't an issue for PC gaming where the graphics card is likely to be able to handle the aspect ratio control anyway. However for external devices, games consoles and Blu-ray players for instance, it may be an issue, although at least the screen is a native 16:9 format which a lot of content is nowadays.

Preset Modes - There are no specific preset modes designed for individual uses like gaming.

Lag

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.

We have provided a comparison above against other models we have tested to give an indication between screens. Those shown with blue bars in the bottom half represent the total "display lag" as at the time of review we did not have access to an oscilloscope system to measure the response time element and provide an estimation of the signal processing. The screens tested more recently in the top half 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 Achieva 27" IPS Zero-G showed an average total display lag of 30.7ms during the initial tests. This lag was pretty high overall, equating to around 2 frames. We measured half the average G2G response time as 7.95ms and so we can estimate that the signal processing is approximately 22.75ms, very comparable in fact to the Achieva QH300-IPSMS which features the same scaler. This makes it a bit too laggy for fast or competitive FPS 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, but being quite a bit smaller than most modern LCD TV's of course. As far as desktop monitors go it is at the large end.

• 16:9 aspect ratio is more well suited to videos than a 16:10 format screen, leaving smaller borders on DVD's and wide screen content at the top and bottom.

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

• The native screen resolution means that some source inputs (especially external devices) will need to be scaled to fill the screen as many will be standard 1080 HD resolution (1920 x 1080). At least with the screen being a native 16:9 format there is less need for internal aspect ratio scaling to be accounted for.

• Digital interface support HDCP for any encrypted and protected content

• Only DVI and VGA connections available, so little connectivity choice for modern DVD players, Blu-ray, consoles etc. It's a shame HDMI wasn't included as an additional option.

• Cables provided in the box for DL-DVI, but not VGA.

• Glossy AG coating may prove problematic with reflections, depending on your lighting conditions and the position of the screen. It can make colours and blacks "pop" though if you like this style of coating.

• Wide brightness range adjustment possible from the display, including high maximum luminance of ~343 cd/m² and a reasonable minimum luminance of ~76 cd/m² (if you switch to the user define mode). This should afford you very good control for different lighting conditions although there is no actual backlight control, and so moving away from the default 75% setting causes contrast ratio to be crushed.

• Black depth and contrast ratio are very good for an IPS panel at 848:1 at default settings, but the screen is too bright really to use. As soon as you move away from that default brightness the contrast ratio is severely impacted. As a result shadow detail in darker scenes may be lost, especially if you are watching a lot of dark content. The contrast ratio after calibration is a weak point of this screen.

• Dynamic contrast ratio not available on this model.

• No specific preset modes available for movies or video.

• Moderate pixel responsiveness which should still be able to handle fast moving scenes in movies without issue. No overshoot issues which is pleasing.

• Wide viewing angles thanks to IPS panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles.

• Limited range of ergonomic adjustments available from the stand, so may not be easy to obtain a comfortable position for multiple users or if you want to sit further away from the screen for movie viewing.

• No noticeable backlight leakage, and none from the edges which is good. This type of leakage may prove an issue when watching movies where black borders are present but it is not a problem here.

• No integrated stereo speakers on this model.

• Limited range of hardware aspect ratio options with only 'full' and '4:3' available. May present problems with some external devices possibly if they output non 16:9 formats.

• Picture in picture (PiP) and Picture By Picture (PbP) are not available.

• For PAL sources, we have tested the screen and confirmed it will support the full native resolution of 2560 x 1600 at 50Hz refresh rate.
   

Conclusion

The 27" IPS Zero-G left us with some mixed feelings overall. Obviously the name of the game here is providing a quality panel at a low cost, so hopefully people understand this means some sacrifices will have to be made. On the positive side, the design looked pretty nice in our opinion and the glossy screen coating is still fairly rare in the market. Thankfully it didn't lead to an overly reflective surface like some other glass-fronted screens we've tested, and those who like the crisp and clean feel of a glossy coating won't be disappointed. The high resolution IPS panel is a joy to work with and it's great to be able to offer this 'retina' resolution at a low cost in the 27" sector. Being IPS it offered some quality all-round performance as well which you might expect from the technology. Default setup of the screen was actually very good, with the only problem being the overly bright default setup. Here unfortunately is where the main problem appears.

While the default setup is very good, including a decent contrast ratio for an IPS panel, the lack of a true backlight control really lets the screen down. Not being able to dim the backlight properly means severely crushed contrast ratios, high energy consumption and even relatively high heat output. True, it is PWM free at the moment for those worried about flickering, but the contrast ratio issue is almost unforgivable. In other areas the screen felt a little limited in functions and features. We aren't bothered about the absence of things like dynamic contrast, as those are rarely useful anyway. However, the OSD menu felt quite basic, the stand was very limited and the connectivity options could have done with an additional HDMI we think. A lot of those features have been left off of course to keep costs down, so in some regards that's understandable. The moderate response times and lag mean the screen isn't ideal for high end gaming, but it can at least handle general all-round uses reasonably well. The price in the UK has not been finalised yet, but we expect this to of course be very competitively priced compared with many 27" models out there. Certainly worth a look if you're on a budget and after a glossy general purpose screen.