Picture Quality

The Cooler Master GM34-CWQ2 features an 8-bit Quantum Dot VA panel capable of displaying 16.7 million colors. The panel can in fact be pushed to display 10 bits of color per channel, by using Frame Rate Control (FRC), a method of temporal dithering, to create a perception of 1,024 individual shades of RGB color (1.07 billion colors in total). Unless you're a creative professional with an established end-to-end 10-bit color workflow, you shouldn't lose sleep over the 8-bit+FRC nature of this monitor.

Quantum dots should be very familiar to everyone who's into television technology, where they've been actively used for more than five years. Samsung is the company that particularly leaned into them – their entire QLED TV lineup featured Quantum Dot panels, which they considered so good that they made a point of steering clear of OLED technology. This of course changed after Samsung released their QD-OLED panels, but those too again feature Quantum Dot technology; that's in fact what the "QD" part of their name stands for. In short, quantum dots are semiconductive nanocrystals, measuring 2-10 nanometers, which are able to produce pure red, green, and blue light. Their exact color is determined by the number of atoms within. They're usually applied to a sheet of film located between the backlight and the panel/color filter. The quantum dot enhancement film then tries to improve various aspects of the picture quality, such as color accuracy, saturation, and brightness. All that while using substantially less energy than a conventional LCD panel, which we already found to be true earlier in the review.

The backlight unit is controlled by direct current (DC), which makes it flicker-free at any given brightness level. The screen coating on the Cooler Master GM34-CWQ2 is light anti-glare (AG). The screen is decently resistant to reflecting its surroundings even when used in a room with a lot of natural or artificial light, and the picture isn't perceived as grainy or dirty from a normal sitting distance, which can be the case with heavier AG coatings. The maximum specified brightness of the panel is 320 cd/m², accompanied by a static contrast ratio of 4,000:1.

As for the image sharpness, 3440 x 1440 pixels stretched over a 34-inch ultrawide panel result in a pixel density of 110 PPI. This gives you sharp fonts, icons, and other visual elements of whatever's being displayed on the screen. You also get plenty of screen real estate to work with, partially because using Windows UI scaling isn't necessary. Simultaneously working in two Windows side-by-side feels as if you're using two monitors, but without ugly bezels splitting the image in half.

To test the picture quality of the Cooler Master GM34-CWQ2, I've used a combination of the X-Rite i1Display Pro, DisplayCAL – a powerful software solution for display calibration and profiling, which is completely free to use, assuming you own a supported colorimeter – and Calman, the industry-standard display testing and calibrating software suite.

Picture Quality at Factory Settings

The picture quality of the Cooler Master GM34-CWQ2 at its factory defaults was tested right after plugging it in and allowing it to warm up for about an hour.


At default settings, the color temperature of the Cooler Master GM34-CWQ2 is set to 7,334 K, with a prominent imbalance in the red channel, resulting in a cold, blueish tint across the panel, and a somewhat lifeless color performance overall. This also leads to lackluster grayscale performance, with the average ∆E sitting at 6.6. The gamma curve looks decent, as does its average value of 2.206. There are some deviations at very low levels and above 90% level (close to full white), but I didn't notice a pronounced tendency to crush shadow detail even with factory settings applied. By default, the panel brightness sits around 222 cd/m², and the static contrast ratio is 2,837:1 – pretty far from the promised 4,000:1 ratio. In its default state, last year's GM34-CWQ ARGB actually looked better, with warmer, more saturated colors and a higher contrast ratio, although with the brightness set far too high.


The default color accuracy isn't particularly good when tested within the sRGB color space, with an average ∆E of 4, and a recorded maximum of ∆E 8.75, partially caused by the oversaturation of some colors due to the wide gamut coverage of the Quantum Dot VA panel. The CIE diagram shows the oversaturation nicely and confirms its presence both in reds and greens.

The white balance can be improved by visiting the Color Adjustment menu in the OSD and changing the Color Temperature setting to User. That gives you access to individual RGB color channels. To get the white balance closer to 6,500 K, I had to set the red channel (R) to 49, green (G) to 50, and blue (B) to 45. I also adjusted the Brightness setting, found in the Picture menu, to 69, that boosted the actual picture brightness to around 250 cd/m², which is a good middle ground for combined daytime and nighttime usage. Let's compare the measurements before and after doing the OSD tweaks.



After adjusting the settings as described above we see improvements to the white balance, much better RGB balance, and vastly increased grayscale accuracy (∆E down to 2.7, from 6.6). The static contrast ratio also saw a minor improvement, but there are no noteworthy improvements to overall color accuracy (it actually got slightly worse). However, with the color temperature now under control, the picture looks much more attractive. Gone is the cold blueish tint and that alone makes the colors look much more vibrant. With that being said, we can't ignore the fact that the previous Cooler Master GM34-CWQ ARGB performed better with adjusted settings; it had a much higher static contrast ratio (5,074:1), as well as significantly better color accuracy (average ∆E 2.71). It would appear that the GM34-CWQ2 is using a worse-quality panel than its predecessor. Neither is suited for professional graphics work, like photo and video editing, before calibration, so you could argue that the measurable differences between them are irrelevant, but the fact remains that you're effectively getting better image quality with last year's model. This is at the expense of some gaming-related capabilities, of course, but more on that on the next page of this review.


As we can see by examining the CIE diagram, we get a 99.9% coverage of the sRGB and a 90.9% coverage of the DCI-P3 color space with our adjusted settings. The gamut volume equals 158.7% for sRGB and 112.4% for DCI-P3 color spaces. These are very good numbers, as well as a clear demonstration of the benefits of adding a quantum dot film layer between the backlight and the panel.


This is what the luminance and color uniformity of the Cooler Master GM34-CWQ2 looks like when measured at 25 different patches across the panel. Please click on the image to see it in high resolution and examine the data in greater detail. The brightness stability has a passing grade. Nowhere did we notice a deviation greater than -10% in relation to the center of the screen, and the biggest offender is the upper edge of the panel, where the brightness is on average 8.01 to 9.93% lower than in the middle. Contrast deviation stays within 5% almost across the panel, which is great.

The Cooler Master GM34-CWQ2 carries a VESA DisplayHDR 400 badge, meaning it can achieve a peak luminance of 400 cd/m². This isn't a mere blank statement; the monitor is capable of reaching a full-screen brightness of around 450 cd/m² in SDR mode. While such above-average brightness and quantum dot technology do improve the HDR experience to a certain extent, the GM34-CWQ2 is still missing a backlight local dimming technology, which is essential for a "true" HDR experience.

Picture Quality After Calibration

I calibrated the display by using the X-Rite i1Display Pro colorimeter and the DisplayCAL software solution. The initial profiling and calibration were done with the luminance target set to 250 cd/m², which presents a happy medium for a comfortable combined daytime and nighttime usage.

Here's what we get after calibrating the monitor.



A proper hardware calibration results in big improvements in color accuracy, gamma tracking, and color temperature. The average color accuracy ΔE went down to 0.48, and the maximum measured ΔE is 2.57, with certain shades of blue showing the largest deviation from the target. What didn't improve is the static contrast ratio. This is an area where the GM34-CWQ2 falls way behind its predecessor, calibrated or not.

Backlight Uniformity

To give you an idea of the backlight's uniformity, I set the brightness of the monitor to 250 cd/m² before taking a photo of the panel in a completely dark room. I did my best to find a combination of the ISO value and shutter speed that would capture the screen in a way that has it look as close to what my eyes were seeing in real life.



There's visible backlight unevenness around the edges of the panel, but it is completely unnoticeable when using the monitor.

Viewing Angles

The viewing angles of the VA panel built into the Cooler Master GM34-CWQ2 are good. There's no visible shift in colors when you change your sitting position. Cooler Master was smart to give the 34-inch ultrawide panel a slight 1500R curvature, which solves any potential vignetting issues around its edges. However, if you move to a more extreme angle to either side, that leads to obvious color shift, as is the case with VA panels.