Good to see you got it fixed.
I run a 5950 with RTX 3090 and 1000 w power supply. It draws 3-400 watts in game. Just like a car engine, you never run a power supply at max. Best is around 50% or less.
The dual cables to video card is also something that often clears the problem. People think that because a cable has 2 connectors that it is ok to use. They overlook that there is only 1 connector on the other end.