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The U27G4XM ships in its Standard picture mode. In the OSD’s parlance, that’s the Standard Game Mode and Standard Eco Adjustment. There are gamut selections available and accuracy is high both before and after calibration.
Grayscale and Gamma Tracking
Our grayscale and gamma tests use Calman calibration software from Portrait Displays. We describe our grayscale and gamma tests in detail here.
The U27G4XM’s default grayscale is a tad cool, but errors barely crack the 3dE threshold, the point where they become visible. Most are below the line, so this monitor can be enjoyed right out of the box. Gamma is right on the 2.2 reference line as well, with no visible issues.
Calibration takes grayscale tracking down to a pro-level 0.42dE. It doesn’t get much better than that. Gamma gets a shade light from 50-90%, but the change is barely visible in actual content. This is excellent performance.
The sRGB gamut mode cannot be calibrated, but it has visually perfect grayscale tracking and slightly light gamma that closely tracks the 2.2 reference. It is suitable for color-critical tasks.
Comparisons
The top three screens, including the U27G4XM, are visually identical in the grayscale test. 2.40dE is a solid result. After calibration, there is no visible difference among the monitors. The U27G4XM’s 0.42dE is a standout result. In the gamma test, the range of values is fairly tight at 0.11 from smallest to largest. Overall tracking is a tad light with a 3.18% deviation representing an actual value of 2.13.
Color Gamut Accuracy
Our color gamut and volume testing use Portrait Displays’ Calman software. For details on our color gamut testing and volume calculations, click here.
The U27G4XM is a very colorful monitor with extra punch across the entire gamut triangle. The default is close to perfect with slight oversaturation and hue errors in red and green. The points track linearly, so there is no loss of detail in any part of the image. Calibration only makes a slight difference that will be hard to see in a before-and-after comparison. But it’s worth doing for the improvement in grayscale tracking. The sRGB mode is better than many pro monitors I’ve tested with an average error of just 0.80dE.
Comparisons
As impressive as the U27G4XM’s accuracy is, it is competing with some equally precise displays. 2.27dE is a great score, but others score better. Is that a difference worth paying for? Not in my opinion, especially when you consider gamut volume, which is the U27G4XM’s main advantage. Amazingly, it does not have a Quantum Dot layer, but it does a great impression of that tech with over 109% coverage of DCI-P3. You will see that in the brightest content where primary colors dominate. There is a good deal of extra red, green, and blue. The sRGB result of 97.93% is nearly ideal and qualifies the U27G4XM for critical tasks.
Test Takeaway: The U27G4XM can be enjoyed without calibration, but a few tweaks take it to reference levels. Gamma is a touch light, but color is exemplary and richly saturated. It has more coverage than the competition, which is a difference that can easily be seen. The sRGB mode is very precise with nearly perfect color and grayscale.
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