So currently I’m running a 5800x and a regular 2060. I’ve got a 650w gold PSU that’s about 4 years old, no problems with it at all. I’m thinking about upgrading to a RX 7800 XT because GeForce prices are perpetually absurd. It seems like it would be enough power, but the few things I’ve read say that I need at least a 750w if I go with the AMD (because they’re power hungry?), but 650w would be fine for a 4070ti. If I have to buy a new PSU, I feel like it would wipe out any savings I might get by buying AMD over Nvidia. How can I definitively know if I need more power?

Full disclosure, I understand the concept of undervolting, but I’m not nearly confident enough to mess with the settings.