Can a PSU affect CPU performance?

In 2020 I built my current Desktop PC for gaming.

An AMD B550 Mobo, 3600X CPU, 16 BG ram with the semi modular Gigabyte B700H PSU (80 plus Bronze).

Since then I've double the Ram to 32 GB and upgraded the CPU twice, first to 5800X and now the 5800X3D.

The system has performed just fine over that time.

I've got an NVidia GTX 2080ti rate at 250W and the PSU has not had any trouble at all.

After upgrading to the 5800X3D I did notice that the Cinebench R20 and R23 scores were a little below average but I put this down to silicon lottery and air cooling. It still ran pretty fast.

I've been looking to replace the 2080ti with a 7900XT and to do that the 700W PSU was on the limit. So with that in mind I saw a deal on a 850W Seasonic Focus GX 850 80PLUS Gold fully modular PSU and ordered it.

The swap out was done in no time and the first thing I then did was fire up Cinebench R20. It scored 3% faster than the last time I ran it a few months ago. Seemed a bit weird and it's possible that BIOS updates may have played a part in this but I don't think so, the last test were done ~ 4 months ago when I upgrade the Noctua fans on the PSU cooler and got a nice reduction in temps but no bump in performance. No Bios updates has been released or applied in that time.

So I then did a full pass Cinebench R23 test and this reported a 4% bump in performance!

Has my PSU been holding my CPU back, what do you think?