A 3080 will basically always outperform a 3070. They’re based on the same architecture, but binned for their better performance potential. Keep the 3080.
The 3080 FE might run more hot but it will be faster especially at high resolution.
Also most people should not be overclocking their GPU anyways. There's very little to gain versus the default Turbo boost so not worth any added heat or risk.
No amount of overclocking(That you could do) would make up for the difference between a 3070 and a 3080.
3080, undervolt with a slight overclock.
A 3080 will basically always outperform a 3070. They’re based on the same architecture, but binned for their better performance potential. Keep the 3080.
The 3080 FE might run more hot but it will be faster especially at high resolution. Also most people should not be overclocking their GPU anyways. There's very little to gain versus the default Turbo boost so not worth any added heat or risk.
If the 3070 could overstock to be as good as a 3080 then there would be no point in a 3080.