I have benched hours and hours with arena chess test (which is like running prime), 3dmark, pcmark, vantage, 32m spi, etc at 4.6ghz, 1.68vcore LLC enabled, 1.6vtt, 1.96DRAM, 1.96 cpu Pll. I had run ~10 prime 12+ hrs runs and many linpack when I first got the cpu, and after all the abuse at high volts, all my stable OC's require exact same vcore, qpi/vtt, etc. I would be surprised if one benching session at those volts did any damage, unless you have a defective part to begin with...or certainly one less viable then mine.

I had one situation, prior to doing any benching where all of sudden I was limited to low bclk...turned out to be a bad stick of ram, solved by putting in one stick of ram at a time.

Also I assume you have reflashed bios, if you are getting weird settings in cpuz. Also I assume you are stable at stock, ie not a corrupt OS.

But if you have narrowed it down to cpu/motherboard already, dont know what to tell you. Best way to investigate is with another cpu, without another cpu or mobo to try, would only be guessing. BTW...screenshot links dont work for me.