fps alway drop to 30

hi friend,

Not sure what is the problem.
Two days ago, I try the IS38 and found when I play the 5 toons, sometime, the fps always drop from 60 to 30 suddently, but after several second it increase to 60 again.
I dont't remember I saw this problem when I lvl up my shaman to 85, I remember it always stay at about 50-60.
But when I reinstall the IS37, the problem still the same.

Any idea what's the problem?

my PC: I5 760, GTX460, 8G RAM

Are you switching windows when it "suddenly drops to 30 fps"? Because the defaults are to limit to 60 in the foreground and 30 in the background, so that would be normal behavior.

Otherwise, it probably depends on what you're doing, or where you are, in the game and I'd need more information to guess at what the "problem" is. 30 FPS is hardly problematic, though. DVDs play at less than that. According to Wikipedia, "Every Hollywood movie is laid to disc" at 23.976 fps ;)