^I did with the MSI board Achim, yes. I tried a lot of things, its hard to make sense of it all - tried one core, two cores, three cores underclocked and it made no difference.
I haven't tried with the Abit yet, but it's no point. Good thing, Abit board has 8-pin 12V :D
This time around I'll keep all cores to 100% stable MHz [i.e. 2.5GHz :)] but one high. If one works for around 20 hours then I'll turn another one up and check for 24 hours - that way I might find a pattern.
When it freezes, it happens out of the blue and it throws CPU load high, even though you may not be doing anything [check power meter or heat].