Is a 750W PSU Sufficient for an i9 12900K and 9070 XT?

You might be on the edge with that setup. Those parts together typically have a total power draw around 545 to 615W, depending on your motherboard and other components. Just keep in mind that other devices like fans and cooling systems could push you over that limit. You might be fine for now, but monitor your system to avoid any surprises.

A 750W power supply should be okay, especially if it's a newer ATX 3.x model. While it may be the minimum for peak performance, you shouldn't encounter major issues since you're not overclocking.

I had a similar setup and my system shut down a couple of times under load. Switching to a higher wattage PSU fixed those issues. You could definitely run with 750W, but just make sure to monitor it closely.

If you're feeling unsure, consider undervolting your GPU. The 9070 XT often defaults to higher wattage settings, and reducing this could actually give performance benefits while lowering power draw.

Honestly, it's a bit tight. A good rule of thumb is to aim for at least an 850W PSU for setups like yours to ensure you don’t overstrain the supply. In heavy use, like gaming or rendering, the demand could exceed what your PSU can comfortably handle.