If that is a constant 60 FPS, v-sync is on somewhere, be it in game or forced on in the control panel.
If it is just around 60 FPS, then it may be off, but I'd look at setting differences. Perhaps you forced on SSAA or some other such insanely demanding settings, or you have changed your resolution choice/down sampled.
Are you playing in the same area. Some maps are different, and online vs single player in particular, things will be different.
If it isn't the above, and it is showing 99% usage, I suspect you have a virus.