Doom3 RoE blank screen

Doom 3 RoEPlays fine for about 5-10 minutes. After that the screen goes completely blank, but the game still runs. I can quicksave my progress before ctrl+alt+del and closing Doom3. The weird thing is that this didn't happen in leve 1, but did in level 2. I ran the 1.3 update and it got through level2 and 3 fine, but it started happening again in level 4. Any ideas?

GIGABYTE GA-K8NS Ultra
Rosewill 500W Power Supply
A64 3000+
512MB DDR400 (2X256 dual channel)
BFG GF6800GTOC
Highpoint RockerRAID100 card
2X WDJB1200JB HDDs
SB Audigy

I tried a different molex connector on the GF6800GT, but that didn't seem to help unless that's why it ran better for levels 2&3. I've got an Antec 475W power supply I could try, but I doubt that will be any better than the one I've got.