Re: G-Sync 101 w/Chart (WIP)
Posted: 22 Nov 2016, 13:46
Yes. I'm not exactly sure what happens at the ceiling with vsync on, but I suspect Nvidia put a framerate cap somewhere in their driver.jorimt wrote:I too thought the minimum number may vary by monitor, but after seeing that both the official and unofficial source stated an almost identical number, we're just to have to assume it's the correct one.Sparky wrote:Let's call the threshold 36fps for now, it may be monitor specific, because as far as I know we only have a sample size of one. That gives us a 20.7ms window to play with(1/36 of a second - 1/144 of a second). so 10 above, 10 below, or maybe they got clever and made the centering of it depend on how quickly and in which direction framerate is changing.
It's not quite possible to have a framerate below zero. The tearing can happen anywhere in the 0~36 range, the issue is how fast it's changing. Say one frame is 31ms(32fps), so the monitor will throw in an extra refresh, say it starts that self refresh at 14ms. If the next frame finishes between 14ms and 21ms(48~71fps), or between 41ms and 48ms(21~24fps), you'll get a tear or delay(depending on v-sync setting), but if instead the next frame is between 7 and 13ms(72~144 fps), or 49 and 70ms(14~20fps), you wouldn't get that tear/delay, because the monitor would have completed its self refresh by then. Also, if the framerate slowly creeps down over many frames, you won't get tearing because the monitor has time to adjust when it does the additional refresh.
I see, so the way I have it split into three sections now ("Below G-Sync Range," "Within 1ms Polling Range," "Exceeds 1ms Polling Range") is redundant, seeing as one behavior is causing all instances.
Basically, it tears when it misses the frametime window with V-Sync off, and suspends with V-Sync on. I'll have to carefully rearrange and word all of this to make it digestible to the average G-Sync user.
Just to confirm, this happens so quickly, there is no way it is adding additional input latency with G-Sync + V-Sync on, unless of course you hit the G-Sync ceiling (where this doesn't occur anyway), correct?
Appreciate the input, as always.