Its good to know - I have plans to use 5900x with 3070 fe but with flex-atx 500 W psu - should be ok if we assume that 3070 uses 100 W less than 3080
Yep, I deliberately haven't even undervolted to test the limits. 3070 should be the sweet spot for flex ATX, 3080 would be stretching it. Mind that my test was carried out on a temporary system with i7-8700k.