You quite simply shouldn't be experiencing input latency with G-Sync + v-sync on + 58 RTSS fps limit. I haven't completed my input latency tests at 60 Hz as of yet, but there shouldn't be a difference; either you're experiencing 1+ frame of additional latency, or you're not. There really is no in-between.MT_ wrote:I have already tried RTSS in combination with G-sync and surprisingly there was noticable input lag. I'm a bit surprised now as the thread start also mentions RTSS with Gsync gives no extra latency? Or is this because I have V-sync enabled as well for frametime stabilization?jorimt wrote:I believe the latest version of RTSS can do decimal capping, you simply have to input it into the actual config file. Haven't tried it myself though.
And yes, the entire point of the fps limit is to avoid G-Sync's v-sync behavior at/above the refresh limit. Not sure if you mean stacking two fps limiters in this case; again, I don't see an advantage.
Also, in my testing, RTSS doesn't add additional input latency with G-Sync, so you shouldn't have to worry about that. And as for "spiking" to 59 fps with RTSS at a 58 fps limit, that is unlikely. Spikes usually cause lower frames, not higher frames. Anyway, you'd have to be at 59/60+ a considerable longer time for G-Sync to start acting like v-sync, which an appropriate fps limit prevents.
The only reason G-Sync begins to act like v-sync at the display's refresh rate limit is because it can no longer adjust the refresh rate to match the framerate output by the system; if you're sustaining 59+ frames for a long period, and the two frame buffers begin to over-queue, this delays frame display, which, in turn, causes the latency (at 60 Hz, double buffer latency is up to two frames delay: 16.6ms x 2 = 33.2ms additional latency).
Good to know on the decimal stuff though.
Another question, if someone ever tested this; Enabling Aero/Compositor in Windows 7 introduces quite some input lag. What happens though in a Windowed game with proper cap? Is it still worse than full screen exclusive? It 'feels' the same when it comes to input lag anyway...
Also how does V-sync work with G-sync in windowed mode? I guess now it uses the compositor built-in V-sync to do the frametime stabilization and such?
There is the simple fact that 58 fps at 60 Hz is a much more noticeable fluidity drop than 98 fps at 100 Hz or 142 fps at 144 Hz, so it is possible you could be mistaking that for additional input latency. It's one of the downsides of a 60 Hz G-Sync display + fps limiting.
As for windowed mode + G-Sync, with the proper cap, it should be the same as exclusive fullscreen in regards to latency. It will however have a 5% performance drop on average over fullscreen mode, G-Sync or no G-Sync.
EDIT: I explain how G-Sync windowed mode works in the OP on this thread.