How can I tell if my PSU is insufficent

[Iwf]

I've 7800x3d, 4090 watercooled solution with a 750 watt power supply. Other than work I mainly use for MS Flight Sim.

Recent testing using 3dmark bench marking and stability tests suggest it's both stable, producing 'excellent' scores with CPU and GPU temps sub 60c. MSI after burner is used to spice things up a bit,. but no other overclocking has been attempted I side loaded a 450 PSU tiggered from the primary so in theory I have 1000w of power available. A power meter records a max of 628 watts on load. But i'd prefer to run only one PSU.

But everything I read suggests 750w isn't sufficient. The exam question is thus how can tell if the system is being throttled. What data should I be looking at?

thanks

 

[Iwf]

If the psu is insufficient you will get shutdowns, black screens and general instability. Personally I would not be running a 4090 off a 750w psu. What make and model is it?

Thanks

It's a Corsair SF750. Never had any problems with it and none of the symptoms you speak of. When I ran the two PSU, I used the 450 to run the PC and the 750 for the 4090, but as I say overall it never seem to draw more than 650w. It's of course possible the Corsair are built well