Graphics Artifacts & crashing with new 6800

I've just bought an MSI nv6800 128 for my shuttle SN45GV2 and all seemed to be fine. Ran 3Dmark 2005 and got a respectable 3500 points. I OC'd up to 375 GPU/800 RAM and achieved 4000! I tried a little higher (390/850) and got artifacts so dropped the settings back down. After playing CoD for about 2 hours on these settings I got severe artifacts (short multicolour wavy lines accross the screen).

As I though the card may have overheated in the case I opened it up and turned the fan to max. The temp on the control panel read only 55 degC and the screen returned to normal. Once the system had recovered I returned all clock settings to normal.

This now keeps happening with case on and off and with the GFX fan at max. I've seen the temp is as low at 47 degrees when it's crashed. The system normall slows for a few seconds with artifacts, then completely freezes with artifacts sometimes restarting 20-30 seconds later, sometimes manually rebooted.

It was installed on a fresh HDD with windows MCE and the latest MCE graphics drivers. I haven't updated the BIOS yet (fubar'd my last comp this way so a little reluctant) and I've also tried the MSI and standard windows nVidia drivers to no avail.

Is the shuttle PSU up to the job? It's the 250W model and the card is only supposed to draw 75W max so prob not.

Do I need to update the BIOS or something or is the card just knackered?

It's a long post but I'd really appreciate some help as I love fans running at <5%

 

did you try running any games before overclocking?

 

I would doubt it. nv6800's are said to be picky about the amp/wattage being fed to them.

There is good news though. I could the card off your hands for, ooh, thirty quid?

 

Hmm, bout £170 off the mark there mate

I'm gonna RMA it back and hopefully pick up a 6800 GT if I can find one that's suitable for my shuttle.

 

Maybe cut a hole for the fan intake in the side panel.

 

The system was crashing at wondows desktop with nothing running with the case off. If I can't get it working I'll go for another 6800 as I've heard most are fine with the shuttle 250W PSU.