I ran Sisoft Sandra Pro on my system at the weekend. One of the more surprising problems flagged was that the VCore was being reported as being below the CPU's minimum voltage - the recommended action was that, if I had underclocked it I had taken it too far!
Now, on the basis that even I'm not stupid enough to underclock my system, the implication is that my system has been running below spec since the rebuild!

Thanks in advance,
AndyG