CPU bottleneck

How many fps do you lose by having an old cpu with the 4080/4090?

I know im being cpu bottlenecked but how many fps would i even get out of spending large amounts of cash to upgrade the cpu? When i upgrade the next time i would have to get a new motherboard, new CPU and probably get ddr5 for the futerproofing.

I upgraded my 3070 for a 4080, but i only got a 10700f. Should i wait for 14th? Probably a new socket for that aswell?