6800gt, repeated short freezes, missing textures

Question

Picked up a 6800GT today. Used ATI's cleaner app to get rid of my old 9700pro drivers, and installed the 6800gt. Installed the newest 61.77 drivers.
I ran Aquamark3, scored 58,536. Next I ran 3DMark. On the second test the screen started to freeze for 3-4 seconds, then it would continue normally for 5-10, then freeze for 3-4 seconds. I uninstalled 3Dmark, reinstalled it, and the problem went away. Scored 11,151.
Ran Doom3, works great. Reinstalled UT2004 (just did a full format a few days ago), d/l'd the latest patch, jump on a server, and its doing the same thing 3DMark did. Every 5-10 seconds the screen freezes for 3-4 seconds, the sound loops rapidly, and then it stops and everything looks great for another 5-10 seconds. Uninstalled 61.77, installed 61.76, still does it. Uninstalled UT2004, reinstalled it, same problem.  Another game I run, Asheron's Call 2, is doing the same thing UT2004 is.  Plus in Asheron's Call 2 I often see textures missing completely.
I would not be surprised if the issue is my PSU.  Its a no-name 350w.  +12v=12a, -12v=.8a, -5v=.5a.  I nearly picked a new one up while in the store.  But I had just finished reading a ton of reviews saying "350w is fine, even 300w is fine", so I figured I'd give it a shot.  Now I don't mind going out and spending the cash for a new PSU, but I'd rather not do it purely for the sake of troubleshooting.  I've already spent the entire day updating drivers, chipset drivers, and everything else I could think of.  But I wont be offended if you suggest something really simple.
AMD 64 3200+
WD 250gig SATA 8mb HD
1 gig Corsair XMS DDR400
6800GT OC
Anyone have any suggestions?

Answer 1

Clocks, are you overclocking your GT?  This sounds like clock throttling to me.  It will happen when you try to OC the card too much.  If you can, download Rivatuner and have it monitor your clock frequencies and temperatures while you are playing UT2k4.  When it freezes, check Rivatuner to see if the clock frequencies changed, or maybe if the temps are too high.
Also, I've heard of some people having problems at stock speeds, but once they took off the HSF and replaced those thermal pads on the memory with AS5 it would work fine.  If it's an option for you, I would put AS5 on the memory and core.