I've ordered a Ryzen 7 7800X3D, 16GB of CL38 memory, and an MSI B850 Tomahawk Max WiFi 7 motherboard. I'd like to install these parts alongside my current RTX 3060 8GB until I purchase a new graphics card. My current power supply is 500W, and I'm planning to upgrade to an 850W unit when I buy the new GPU. Would the 500W PSU be safe to use for a couple of weeks, or should I wait for the new power supply first?
3 Answers
The safest choice is to wait for the new power supply, especially if the 500W unit is old, low-quality, or lacks the right protections and connectors. A temporary failure would probably just trigger the PSU’s protection and shut the system down, but it isn’t worth risking expensive new components.
A Ryzen 7 7800X3D and RTX 3060 don’t normally draw an extreme amount of power, so a good-quality 500W PSU may be able to handle the system at stock settings. The exact model, age, condition, and efficiency rating of the PSU matter a lot, though. Avoid overclocking and heavy power-limit tuning until you upgrade.
The new CPU may not use more power than the Ryzen 5 5600 it replaces, so the graphics card will still be the main load. If the existing PSU is a reputable model in good condition, it could work temporarily, but waiting is the more conservative option when the PSU’s quality is unknown.

My current system uses a B450M-A board, Ryzen 5 5600, 16GB of DDR4, the same RTX 3060, fans, and the stock AMD cooler. I’m not sure whether that gives enough information to judge the PSU.