I had both chips on the bench this week (returning one) so I ran a quick 1440p gaming comparison on the same 4080 SUPER, 32GB DDR5-6000 CL30, same Windows install.

Averaged 1% lows across CS2, Cyberpunk, BG3, and Hogwarts Legacy: the 7950X3D was within 1-3% of the 7800X3D in games — basically margin of error — and occasionally LOWER when the scheduler parked the wrong CCD. The 7950X3D obviously crushes it in multicore (Cinebench ~38k vs ~18k), so if you render or compile it's a real upgrade.

Verdict for a pure gamer: save the money, buy the 7800X3D, spend the difference on the GPU. Happy to run more titles if people want specific games.