This is great! I guess the problem must lie with the PSU (some other way I can comfirm this?). It is a little older than 4 years and it is an AOpen Z300-A.
Your proof is in the results...
A 4 year old, modded Aopen PSU is the exact problem. All PSUs, regardless of quality degrade in performance after time. The cheaper, the quicker that happens. If your system isn't getting the right amount of "juice" it can do all sorts of crazy things, from crashing, overheating, turning off.
It isn't until you have a PSU problem that you realize how important a component it is.
NM... I stopped at your post before that
What kind of heatsink are you using? 62 C is hot... but it is possible that if your using a stock or cheap HSF and/or your case ventalation isn't good, that is going to be your temp. What sort of case are you using and what is the ventelation like?