Originally Posted by
watercooled
Flash causes another interesting problem on some cards, it will set the GPU to it's video playback clock, somewhere between idle and load clocks, probably to lower power consumption when playing videos. However, the clock locks at this frequency while a flash video is open, regardless of whether it's actually playing. This kills performance in games; I first discovered this after frame-rate mysteriously tanked on whatever game I was playing at the time, but it seems it's a common problem if you search. Unfortunately it's not very well known, and I imagine loads of people will have some YT videos open in their browser while playing a game...