OC Stability Questions

[xBlizzDevious]

I've been stress-testing my computer lately as I've had some issues with Vivaldi (browser) and they asked if there are any hardware faults.

Memtest ran for ~24 hours, did a few passes and had no errors.
So I ran Prime95 for ~21 hours. Again, no errors, but I noticed that some threads were behind others by quite a way. (See screenshot) The range is from ~550 up to ~900 tests completed depending on thread.

 

 

So I Googled it and found that it could be an issue with not enough voltage. So I upped the voltage from 1.35V to 1.36V and got a much more consistent result (817-831):



Temperatures are still OK though a little on the high side (78C on small FFTs at max load).
Is this likely to have caused any issues in the past? Obviously there are no errors showing but if threads are that far behind, that seems odd and likely to be an issue.
Is 1.36V going to really damage the CPU? It's an Intel Core i7 3930K and it's been running on 1.27V for a few years followed by 1.35V for a couple more. I don't imagine the 0.01V bump will kill it but I don't want it dying next week!