You downgraded the PSU wattage?
I found that even with my old 5800X3D and 3090 Ti and all the other peripheral devices I was seeing up to 680W total power draw (as reported by my UPS.) Thing is, there’s no way to track instantaneous spikes in power draw without a fairly sophisticated volt/amp recorder. I never had any problems with a 1000W PSU, but I’d be concerned if I only had 750W on tap.