To perform these tests, we use a high-speed camera that shoots at 1000 frames per second. Analyzing the video frame-by-frame allows us to observe the exact time it takes to go from a zero-percent signal to a 100% white field.
The pattern generator is placed at the base of the monitor so our camera can capture the precise moment its front-panel LED lights up, indicating that a video signal is being received by the monitor. With this camera placement, we can easily see how long it takes to fully display a pattern after pressing the button on the generator’s remote. This testing methodology allows for accurate and repeatable results when comparing panels.
Here’s a shot of our test setup. Click on the photo to enlarge.
The brighter section of the camera’s screen is what actually appears in the video. You can see the lights of the pattern generator in the bottom of the viewfinder. We flash the pattern on and off five times and average the results.
Here’s the screen draw result.

A 25-millisecond result is just what we’d expect from an IPS screen. Even though IGZO technology has the potential to improve on this aspect of performance, we believe the display’s electronics are the limiting factor. Moving almost 8.3 million pixels requires a lot of bandwidth and it’s going to take time for all the different components to catch up.
Here are the lag results.

If high-speed gaming is your primary reason for buying a 4K screen, Asus' PQ321Q is the better choice right now. For those with super-fast reaction times, you would be better served by a TN-based display equipped with G-Sync, or some other display with a 120 or 144 Hz refresh. Asus and Dell are marketing these as professional-, rather than enthusiast-oriented products. Dell takes that a step further with its selectable color gamuts and precise accuracy. As we’ve stated before, 4K gaming requires two things right now: big compromises and a pile of cash.
- Dell UP3214Q 31.5” UHD Monitor, The Ultimate Pro Tool?
- Packaging, Physical Layout, And Accessories
- OSD Setup And Calibration Of The Dell UP3214Q
- Measurement And Calibration Methodology: How We Test
- Results: Brightness And Contrast
- Results: Grayscale Tracking And Gamma Response
- Results: Color Gamut And Performance
- Results: Viewing Angles And Uniformity
- Results: Pixel Response And Input Lag
- Dell UP3214Q, Accuracy Beyond Compare

Yes, but you miss the point.
This is a reasonable expectation, with economies of scale the average consumer will eventually be able to buy a 4K display for $300-$500 USD.
Agreed. I've owned a few Dell Ultrasharp monitors and have always been surprised at the short length of warranty compared to what I get from other premium components. Sadly the entire display industry is like this in terms of warranty coverage.
You also miss the point. I assume you didn't even read the article.
Anyway, great article. I was hoping TH would get around do doing a proper review of this monitor as I'm expecting it to be the benchmark for future 4K panels.
We hope to test the P2815Q very soon. In the meantime, we have the UP2414Q in the lab now. This is a 24-inch IPS screen for around $1200.
-Christian-
$3500 16:9?????? Good grief!