Cooler Master GM34-CW 34-inch Gaming Monitor Review: Color For Days

Massive color gamut with 144Hz, HDR and FreeSync.

Cooler Master GM34-CW
Editor's Choice
(Image: © Cooler Master)

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The GM34-CW comes set to its Standard picture mode. That allows access to all image adjustments in SDR mode. Other presets lock out the all-important color temp and gamma options.

Grayscale and Gamma Tracking

Our grayscale and gamma tests are described in detail here.

In the default chart, you can see a gradual decrease in the green level as the picture becomes brighter. This is both a flaw in grayscale tracking and a contrast control that’s set too high. That is further demonstrated by the dip in gamma tracking which runs too light over the entire brightness range. This makes the picture a bit washed out and flat; far below its potential.

Calibration fixes these issues, though there are still some minor flaws here. Gamma is a bit too dark at 10 and 90%. Some very fine detail might be hard to see but in our experience with games and video, this wasn’t a big deal. The 100% step still has a slight reduction in green, which might show up as a purple tint in the brightest highlights. But again, the error is hard to see in actual content.


The GM34-CW comes in last place both before and after calibration. That said, the final score of 1.68dE is acceptable as all errors but one are invisible. This is far from a deal-breaker. Actual content looks fine.

Gamma tracking is close to the 2.2 standard for all brightness steps except 10 and 90%. These two measurements spoil the value range score. With only a 1.82% deviation from 2.2 though, color saturation tracks well, and detail is sharp and well-defined in all areas of the image.

Color Gamut Accuracy

For details on our color gamut testing and volume calculations, please click here.

You can see just how large the GM34-CW’s color gamut is in both the default and calibrated charts. Green and blue are nearly spot-on the DCI-P3 standard, while red is slightly oversaturated. Out-of-box color is good, but whites have a slightly purple tint. Green, cyan, magenta and yellow also are a bit off in hue.

Calibration reduces the average error by half and fixes the hue errors in cyan and yellow. Green and magenta are still a bit off, but less so. And white is right on the money. If you’re looking for an sRGB mode, there isn’t one. Color purists might miss that feature, but very few extended-color monitors come with one these days. Most users will likely enjoy the extra color in all content, even if it’s not entirely true to the creator’s intent.


The average error range for the group is small and none of the monitors have more than slight color issues. The GM34-CW has no visible problems nor do any of the other screens.

The gamut volume chart will likely make the purchase decision for many enthusiasts. 98.11% is the largest DCI-P3 volume we’ve recorded save for the massive 110.23% score we measured from Acer’s CP7271K, which costs twice as much as the GM34-CW. You’ll see that extra color in all content, SDR and HDR. That will make it challenging to use for color-critical work, though you can control the gamut with a software profile. There’s no missing that saturation though; the Cooler Master is very colorful.

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Christian Eberle
Contributing Editor

Christian Eberle is a Contributing Editor for Tom's Hardware US. He's a veteran reviewer of A/V equipment, specializing in monitors. Christian began his obsession with tech when he built his first PC in 1991, a 286 running DOS 3.0 at a blazing 12MHz. In 2006, he undertook training from the Imaging Science Foundation in video calibration and testing and thus started a passion for precise imaging that persists to this day. He is also a professional musician with a degree from the New England Conservatory as a classical bassoonist which he used to good effect as a performer with the West Point Army Band from 1987 to 2013. He enjoys watching movies and listening to high-end audio in his custom-built home theater and can be seen riding trails near his home on a race-ready ICE VTX recumbent trike. Christian enjoys the endless summer in Florida where he lives with his wife and Chihuahua and plays with orchestras around the state.