My interpretation is that the drivers are doing some kind of automatic syncing to monitor refresh rate even if the vsync is not turned on.lenc wrote:Wow, I just installed the new Nvidia driver and the FPS has suddenly dropped to about 70-80 Nothing else has changed as far as I know.
If I didn't cap the frame rate to 200 FPS by using CPU sleep, I got about 240 FPS, but if there was even 1 ms of sleeping for each frame, the frame rate dropped to about 64 FPS. In T1 version the sleeping was disabled but in T2 it was enabled again (in case that the user has disabled vsync).
So, the drivers might interpret sleep system call as a signal to cap the frame rate to monitor refresh rate. Sounds crazy, but I didn't come up with any other explanation. With regards to smoothness, this shouldn't be a problem as far as the resulting frame rate is higher than the monitor refresh rate.
You could still try what happens if you turn vsync off in DSJ4 Setup and force vsync on from NVidia settings. This way DSJ4 won't do any sleeping (it thinks vsync is on) and you will see what's the maximum frame rate.