Pentium 4 3.0e
1GHz PC3200
Radeon 8500 64mb
My Radeon 9800 Pro died 2 weeks ago, its in for repairs

I've been messing around with some pvp characters and noticed this doesn't seem to kick in in that area.. It very well could be my card overheating, or something similar. I've updated my drivers, scanned for viruses and spyware and defragged. I changed my AGP aperture size to 64 to see what would happen, and for a while it didn't happen. But eventually it started up again.
Its strange, I play other games with no problems. World of Warcraft(don't hate me), Counter-Strike: Source and other similar games. I ran Everest and noticed this "DirectX Hardware Support DirectX v8.1" So I wonder if that has something to do with it..
The fact that it starts to happen over time really makes me think its an overheating issue, but if anyone has any suggestions I'd be quite happy to try them out. Thanks!
P.S. I forgot to mention, if I alt tab out of the game the problem seems to go away for a while.