jibbajabba wrote: » It is very much so a thing ... Even if you buy two seemingly identical CPUs, there still might be differences in steppings and you will end up with an incompatibility which is enough to make vmotion impossible. I had two 56xx CPUs here which have the exact same writing on it but when using certain tools it turns out that some instruction sets are different. Based on Intel one of the CPUs had a "service pack" which added some additional features. We had to return both CPUs and buy a "matched pair" .. Oh and in our case EVC didn't even work...