I agree. Send the CPU heat out the back, not into the PSU. Doubly so if you are running the PSU at over 50% of its rated capacity. A PSU failure could leave your entire system as nothing more than junk, because it could fail during a write - which could leave your FAT as nothing more than toast if the write is to a critical system file.
The__Goo mentions a liquid cooling solution. That works fine, unless a hose or seal fails. Then what do you have?
Sizzle. Dead. And just that fast. Toast.
This 'need' to push to the outer limits of the hardware, I will never understand. Let it do what it is designed for, and upgrade from that point on.
Because face it. An extra percent or two is hardly worth the effort, nor the cost. You would not even notice it if you were not wasting so much time in the calculations. And then, it is simply a head trip to convince yourself that you have a 'SUCH' faster machine than what you started out with.
Wow! I can do in 100ms what I could do in 108ms before. Big deal!
The time you take gloating more than overcomes the time you have saved.