Got a shot of 4.5GHZ?
If you got proper cooling then Vcore=1.5v can be OK for 24/7, but how much "unsafe" VVT you are pushing for those Uncore>@4200 24/7? VVT may be a bigger problem, not because it will necessarily kill you (even tho this may do it faster than high Vcore), but because it puts too much stress/heat on PWM/system, and the CPU-temp raises too.
The extra stress/heat generated by high VVT and Uncore (x5 RAM multi) was so much that I found it to be far from "sweet spot" for 24/7 use (at least on my setup).
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