Last night I looked into it and mine was not set to VSync at all. I set it and for most of the session I had flat lines on processor use with no spikes at all. In the last 15 minutes I did get the occoisional spike and micro stutter, ut I don't know why.
definately worked better with Vsync on.
Question If you have VSync on shouldn't the FPS be around 60 or slightly below all the time ?
Vsync will lock the fps to the Monitor's refresh rate. Depending on what that is, the fps will be different.
However the fps can still go down, or spike a few fps above the refresh rate. That's normal!
To really understand how this all works you have to look at "fps" as "from frame to frame timings".
If you fps drop, you'll see a kinda big stutter. At least if you use the standard vsync and not fast, adaptive, etc.
So the fluctuations might be like this:
60 fps = 16.67ms from one frame to the next.
Frame1 -> 16.67ms -> Frame2 -> 16.67ms etc.
Now if the fps drop, it will be like this:
Frame 1 -> 16.67ms -> Frame 2 -> 16.67ms, fps dropping -> Frame 2 again! -> 16.67ms -> Frame 3
So between Frame 2 and 3 you'll have 33.34ms, resulting in a stutter. Now the thing is, that "fps" is often measured multiple times per second, which results in "estimated fps values", actually rather showing the "frametime average over the last measurment duration".
So if the fps drop for a few frames, you'll see something like 58 fps and when the PC gets to keep up again, you'll see a slightly higher fps value than 60.
I don't know why the performance gets worse after some time into the session. I guess it's down to the weather or time of day changing? Or maybe your apps show more than in the beginning? Leaderboard apps showing longer numbers for the gaps, More cars close to you or something?
