@jorimt
jorimt wrote:RTSS does add 1 frame of delay, but that is way better than the 2+ frame delay experienced with uncapped G-SYNC + V-SYNC.
One thing to note here: RTSS "rounds up" to 1 frame of lag. It depends on how much time the frame took to render. For 60Hz, if the frame took 10ms to render, then RTSS adds 6.7ms of lag, not a whole frame. Obviously in high-framerate games like CS:GO and Overwatch, frames take so little time to render than RTSS ends up adding almost 1 frame of lag.
Another important thing is that RTSS does (in theory) not add any delay if the cap is not reached. However, if the cap is reached, input lag still doesn't get higher, because not having reached the cap means there's pre-rendered frames queued up. Reaching the cap keeps those extra queues empty (RTSS can not prevent the game from queuing frames if it's currently not limiting the frame rate.) In fact, RTSS
reduces input lag in most games when the cap is reached.
This is a behavior I observed in most games (except games that focus on low latency, like CS:GO, Overwatch and Paladins, where I simply can't tell the difference without equipment.)
This is even true with "max pre-rendered frames" set to 1. The effect gets worse with higher values. To give an example, if I play Witcher 3 or Fallout 4 with a cap of 90FPS in RTSS, if the game runs at 89FPS or lower, there's more input lag than if it runs at 90FPS. It would appear that not reaching the cap means two frames of lag, reaching the cap means 0 to 1 frame of lag. Raising MPRF introduces additional frames of lag when the cap is not reached, and has no effect if the cap is reached.
In the case of Witcher 3, this is also true when using its own frame limiter (configurable through the game's ini file.)
It seems that frame rate limiting results in what many people claim MPRF 0 did in very old driver versions where (according to those people) it removed a whole frame of lag compared to MPRF 1.
This is easily testable by raising MPRF to maximum in profile inspector and making sure the game is not able to reach maximum refresh ("Ultra" details usually help here.) Then, cap FPS to 2 or 3 FPS below what the game currently renders at. All that input lag goes away. Again, this is even true with MPRF 1.
So in fact, capping to a lower value than you normally would, even with RTSS, can help reduce input lag. If your game usually runs at 90FPS and you cap to 142, you're getting some input lag. Capping to 88 instead reduces input lag.