Results: Pixel Response And Input Lag
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 will actually appear 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.
The next chart includes screen draw results:
Our test results show that for IPS and PLS panels, the draw time is always between 20 and 25 milliseconds. Only TN screens are faster, which is why they are still favored by gamers. The IGZO panels used on the 32-inch Ultra HD products should respond more quickly due to their greater molecular mobility. But that potential hasn’t been tapped yet, most likely because of processing bandwidth limitations. The UP2414 leverages good old AH-IPS technology, so it slots in right where you'd expect.
Like the UP3214Q, this 24-inch 4K screen is not great for gaming. The input lag on both Dell monitors is just too high for titles that require fast reaction times. We’re quite anxious to get our hands on Dell’s 28-inch 4K display, the P2815Q, because it’s not only the least-expensive 4K screen out there, but it’s also a TN-based panel. For now though, it seems that IGZO and IPS high-res displays need to up their processing power before they can be part of a high-performance gaming rig.
