8800 GTX Randomly Freeze, Sound Continues (Card verified to be the issue)

Question

So I just built a new system a few weeks ago:
MOBO: MSI P35 Platinum Rev 1.1
Video: MSI NX8800GTX-T2D768E-HD OC
Core: Intel e6850 Core 2 Duo
Case: Antec P180 Case
PSU: Antec True Power Trio TP3-550
So I can play a game for maybe 2 or 3 days straight(for hours on end), no problems at all.
Then out of nowhere, I get freezing after maybe 5 - 20 minutes of play.
The freeze is a full-video freeze, but the sound continues to play in the background.
I can't alt-tab or ctrl-alt-delete out of it, though I can ping the computer from a different box. There is no BSOD or error message of any kind.
The only way to get out of it is to hit the restart button on the computer.
After I restart the computer, and game, I play for another 10 minutes and get another freeze.
The cycle just continues after that, freeze after freeze.
The next day, I try to play again...and once again no freezes at all for several days.
I am using NVIDIA 162.18 drivers, but I have tried some older and newer ones.
This is on a fresh Windows XP Pro SP2 install, with newest drivers, and a few games.
I am under the assumption that the TP3-550 is plenty to run this video card.
It has the 2 six-pin PCI-E leads, and the motherboard accepts an additional 12V molex for additional power.
I also assume that if power was the issue, the freezes would occur at a regular interval.
What could be the issue? How do I go from no freezes at all one day, to every 15 minutes the next? I am thinking driver issues, but this card has been out for quite some time.
I've had the freezes occur in Company of Heroes, Fable, and Warrior Within
GPU Temp is running at 60 idle, 71 - 74C under load.
Though I have had it crash at 61, and 72 so I don't think that temp is the factor.
I know people sometimes have issues with the 8800 series freezing. It just irks me that it works great for days at a time, then randomly freezes.
Do I RMA it? Or just deal with the occasional freeze?

Answer 1

Ok,
I now have 2 things. A better description of the problem, and results from a different machine.
I tested my 8800GTX(factory OC settings) on an AMD single core processor, Asus Mobo, and an Antec TP3 - 650 power supply (the same power supply as mine, but 100 more watts).
I ran human head on his box and encountered the exact same result (as below) within 5 minutes.
The nature of this freeze is as follows.
1. Running human head for 5 - 30 minutes at factory settings, causes the crash to happen 100% of the time.
2. Randomly, I will hear the audio pause for a second or two, and the graphics freeze immediately.
3. The music than starts back up, and continues to play, but the graphics remain frozen.
4. The mouse can be moved around the screen, and hitting the cntl-alt-del combo causes the mouse arrow to turn to an hourglass.
5. The hardrive lights continue to flicker.
6. 2 to 3 minutes later, I get a BSOD with a minidump, and the system immediately reboots.
I have yet to analyze the minidump, but I assume that it will be irrelevant.
What irks me is that I was able to verify this issue on 2 systems at this time, and I have already RMA'd the board to msi once. They were not able to verify it, though they say that they ran 3Dmark06 on it over several passes.
My problem is that 3Dmark allows pauses between tests, which may clear the memory, or allow it to cool, or whatever it does. Human head does not have this feature.
So now I have to pay for the shipping, and basically demand a new one, whether or not they can verify it using 3D mark.
The only other thing I can guess is that the True Power 3 550(and possibly the 650), is not powerful enough to power this card.
I would think that the 2X 18A(and 2X 19A on the 650) would be enough though, and my friend was running his test on much lesser system.
I'm out of options, and hope that I am not stuck with this faulty card.