[I'm a reviewer] Quirks measuring input lag of ROG by camera
Posted: 01 Aug 2014, 03:00
Hi there!
Recently I received the ASUS ROG Swift for review at PCTuning.cz. I decided to measure also the inputlag of this screen.
Since the flash stopwatch/timers are quite a BS I went for my implementation.
Done in Qt and OpenGL, it renders around 1000 fps with timer info in milliseconds in columns + fps in the middle of the screen.
It works rather well, You can detect even quite small differences in inputlag, also you can see how long it takes to fully switch the pixels etc.
The weird thing is, that in clone mode at the same frequency, both screens are perfectly in sync regarding the refresh signal.
For CRTs its quite OK to see it, makes sense, since the GFX drives the signals. For CRT + LCD it begins to be a bit strange. I always thought that the LCD uses its own refresh signal, but here its synchronized. Even if its connected trough DP or DVI. Finally two LCDs, and same perfect synchro. Why do you think this happens? Is it the GPU that gives the refresh signal to the LCDs/CRTs?
Recently I received the ASUS ROG Swift for review at PCTuning.cz. I decided to measure also the inputlag of this screen.
Since the flash stopwatch/timers are quite a BS I went for my implementation.
Done in Qt and OpenGL, it renders around 1000 fps with timer info in milliseconds in columns + fps in the middle of the screen.
It works rather well, You can detect even quite small differences in inputlag, also you can see how long it takes to fully switch the pixels etc.
The weird thing is, that in clone mode at the same frequency, both screens are perfectly in sync regarding the refresh signal.
For CRTs its quite OK to see it, makes sense, since the GFX drives the signals. For CRT + LCD it begins to be a bit strange. I always thought that the LCD uses its own refresh signal, but here its synchronized. Even if its connected trough DP or DVI. Finally two LCDs, and same perfect synchro. Why do you think this happens? Is it the GPU that gives the refresh signal to the LCDs/CRTs?