Sorry to come back to this old thread, but I actually have a bit of news regarding this issue.
Since upgrading to Win10, I've tried to get some higher OCs just because I wanna see what the new BSODs look like (not joking).
With my history of cold boot loops when enabling internal CPU PLL overvoltage, I definitely got a BSOD with it disabled.
A special note about this BSOD is that I don't get it when stress testing the CPU. It only BSODs at idle, not load! (This is an entirely separate issue that I've seen on other threads, so I'm not sure how strong the correlation is with cold boot loops.)
I was already OCing anyway, so I figured that I might try to enable it to see if it's any different under Win10.
The OC results were as I expected, stable with higher OC and no BSOD at idles (or light loads).
After shutting down and powering on my system several times, I saw NO COLD BOOT LOOPS.
Even after turning off my system overnight, I saw no boot loops the next morning when I powered it on.
So far, it's only been 24 hours; will report back later if I get a cold boot loop!