I think i misunderstood your problem.
If it crashes under load, then I'd be looking for a heat dissipation problem, or cpu / memory voltages being set too low.
Try running a couple of torture tests to start off:
- Download Prime95 and install.
- Run Prime95, click 'just stress testing'.
- Click 'Options' -> 'Torture Test'.
- Choose 'small ffts' and click OK.
- Allow to run overnight.
- Check for errors.
- Repeat above choosing 'blend' for the test type.
Checking for errors:
Prime95 should continue to run tests until you stop it OR until an error is detected.
If an error is detected, check the log (displayed automatically) for messages like "FATAL ERROR: Rounding was 0.5, expected 0.4" AND/OR "Hardware Failure Detected..."
If you see the above errors with Prime95, then it indicates a hardware problem (like cooling or voltage)
Post back and let me know how you get on.
Damo