It's the fan...sounds like it's only second away from death. Probably only a bearing shaking loose, but hey, what do I know?
How easy would it be to fix? Or, if it's not worth the hastle (and I'm as happy for a genuine reason to upgrade as the next guy), what can I get in AGP for less than £150 that's actually going to make the upgrade worthwhile?
Scan's got a 256MB XFX 6800GS AGP, Mem 1000 MHz, GPU 350 MHz, 12 Pipes, Dual DVI-I, HDTV, S-Video/TV Out for £151.28 with Dual DVI.
The other thing is that I'm thinking of getting a 24" Dell at some point, and might be able to justify spending a little more on a card that's going to be able to play games at the native res of a 24incher. What do you reckon I'm going to need for a GPU?