i get random fps drops to like 90 fps for several seconds here and there. but it's not "smooth" 90 fps, but choppy like if there was a connection issue / lag. when i restart my computer it's usually gone the next game. i'm using whatever client is included in the cpmpickup package. anybody know what this could be and how to fix it?

system:
i5-3570k
radeon 7950
16 gb ram
win7 64bit

thanks.