Don't know. OS shouldn't matter if your system was truly stable in Win7.
I don't have any problem in windows 7 x32 and x64..
My O.C on windows 7 x64 is 3.66Ghz (333 x 11)
Stable for my everdays workin...100%.
But if i run on windows 8 dev x64 it frozen when try to open any file or software,..:(
The stable o.c for me on windows 8 dev x64 is 3.33Ghz Max..
Why this happen?Any idea?