It seems to depend on the specific psu. I know people running 750 & 850w PSU’s are running into problems. However I’m running a Seasonic Prime Ultra Platinum 650w with a 3080 and 3700X (PBO on) with zero issues. I’ve even seen a review where they built a small system with a 3080 and Corsair SF600w and benchmarked it without issues. If I was buying a brand new psu I would go for the extra headroom of a 750 or 850w. NVidia’s 750w recommendation if you read the small print was based on using a 10900k, a very power hungry cpu.