Personally wouldn't go lower than 850w. I'm on a 13900k with a 5080 on a 3 year old 850w seasonic and I'll for sure be getting a new PSU soon.
850w is the minimum recommended for a 5080. PSU's degrade with age, an older 750w is cutting it way too close.
850w is the minimum recommended for a 5080. PSU's degrade with age, an older 750w is cutting it way too close.