History: -FPS

The average frame-time for most game projects is around 10ms to 30ms, anything above 100 fps does not make any difference at all for the slow human eye. What really provides the impression of smooth rendering is a constant framerate and, that's most important on modern flat screens, use of v-sync.

On a multitasking OS the worst that can happen to your game is some other processes that consume a lot of processing power. So make sure they can't cause too many problems by raising your games task priority a little bit. The "above normal" priority will do a good job in most cases here.

Also make sure to measure the rendering time for every frame. If you have a lot of frames that take more than 1/60th of a second, just adjust the game to target 30 fps. Keeping constant 30 fps will provide a much better impression than trying to do 60 fps and skipping a frame every now and then.

Also try to tune your frame rate to the display refresh rate. 60 fps on a 100 Hz screen just look awful, better waste some time and try to use 50 fps.