I have done quite a bit of reading on this and there does not seem to be any definitive information regarding the maximum vcore for sandy bridge that is appropriate for 24/7 use. Opinions seem to vary pretty widely. On one hand there are "guidelines" stating to keep it below 1.35, and on the other hand there are technical reps from a motherboard maker which imply that 1.42 is a fine starting point and that up to 1.52 is ok so long as temperatures are under control. The same source stated that Intel told him/her that 1.57 definitely will cause degradation.

I was wondering if anyone has definitive information on this topic based on hard facts from a reputable source.

I apologize in advance if this issue has been previously settled in another thread.