It seems very strange, at least to me, despite the fact that you have the latest bios, and almost everything seems fine, that you had this issue. This motherboard is more than capable to handle that processor not only in stock clock, but with proper cooling, for example a fan blowing directly the vrm, can easily do 4.5 ghz. When you had windows 7 installed, did you observe a crash similar to that when you had windows 10 installed, or the system worked flawlessly all the time? Also, tell us if xmp is enabled, and if you have tried to disable apm from the cpu configuration. Apm is responsible to keep the processor in tdp limits (so even if you had your computer set in high performance mode from windows, the cpu itself when on full load, could downclock and downvolt, simply not to exceed the tdp limit). The other energy features don't affect the performance of the processor, but this one specifically, apm, is known to cause this issue. Also, turbo core should be disabled with apm, as it is preferable for the stability of the system. One more thing to try, is to switch if possible, the ram modules from slots 2 and 4 to 1 and 3 and to check again the performance of the system (if that doesn't work, try with one memory stick, for example in slot 2). It is worth, as you did, checking almost everything in your system, it might definitely be the most beneficial process to check properly your system for errors (it is of course tiring, but the results are worth it).