Does your graphics card make noise?

My macbook pro's giving me a headache... literally, and figuratively. Whenever I do anything that might involve a large portion of the screen refreshing (scrolling this webspage for example, or changing a layer's opacity in photoshop) my macbook emits this sort of high-pitched staticy noise. The closest sound I can compare it to is the buzzing that my power-supply makes.

I'm especially susceptible to getting headaches from high-pitched computer noises. The sound of CRTs drive me crazy. This isn't exactly comparable to that noise (it's not constant), but needless to say it's giving me a headache.

It's also been freezing up a lot recently. I attributed it to a buggy install of snow-leopard but I've since done another clean install and it still hangs pretty frequently.

So, two questions:

First, is this normal? I don't seem to recall it doing this until recently, but maybe I just missed it.

Second, if it's not normal, is this something that might be indicative of a failing graphics card? And if that's the case could my hangups be related to it?

My MBP is the model that initially had the faulty Nvidia 8600M gpu. My first one failed and apple replaced the logic board. They claimed the new one they replaced it with wouldn't have the same problems, but I'm starting to wonder.

Any ideas?