As for stability I run 10 passes of Linpack for initial testing and 20-30 passes of Linpack and 3 hours of Prime95 blend for final testing then its back to crunching. If I don't get any errors reported over the next few days or none of my games freeze while playing then I am stable enough. I've got about 8 months of down time from crunching to catch up on. I've got no time to waste on excessive stability testing.