I'll ask again...how old is the PSU???
And this PSU will not cut it for a 3090ti.
???
When working properly, it should be enough. Again, I ran a 12900K (at stock uses more power than your CPU) and 3090 Ti Suprim X with a 750W unit. Worth noting, 600W is the power taken from the WALL, not what the PSU is outputting. The PSU itself, assuming 90% efficiency, is actually using ~540W which is well under the limit.
Also worth noting, when are those loads realistic? When are you using 100% CPU like in a stress test while gaming? Also, what test did you run to load the GPU? Please not Furmark, lol. Unless your use case is running the CPU at 100% like a stress test (think rendering, maybe
[email protected]) and the GPU at 100% you're fine. I'd bet your gaming wattage is much closer to the 500W (~450W actual) value than it is 600W...
Once again thanks for the advice,
Happy to help, but it feels like you're walking away with the wrong idea (that PSU isn't enough) ATM. Again, if it's working right, it should be fine... at least hold you over until you can save up for a new unit if the 3090 Ti kills the bank.