
And slowly keeps "freezing" until eventually I'm left with something like this, random textures and patterns across the screen.

Minimizing and restoring seems to help, as does restarting the client, but it's rather annoying to have to do that every time this happens. Any ideas? Computer specs for those interested:
nvidia geforce 8600 gts
2gb ram
500w psu
hp pavillion a1644x standard mobo/processor
GW normally runs at 60 fps when it's not doing this, so I'm pretty sure it's not the hardware.