A couple of questions for you:
1. When you were stable with 4.3ghz @ 1.200V on the stock cooler how did you test stability?
2. I see in another forum that you just recently reinstalled the Noctua cooler, what are your current temps at just before the system BSODs?
4.3ghz @ 1.424V would suggest to me that this is definitely not a voltage problem, that's a crazy high voltage for that level OC. Side note: I wouldn't run that high of a voltage on air, that voltage is liquid cooling territory. I'm suspecting since you were stable with 4.3 @ 1.2V and you lost that stability by only changing the CPU cooler that you may not have it seated completely and that the chip is getting too hot and it is shutting down as a safety measure to prevent damage.