So, in retrospect, I didn't need a bigger PSU, I needed a more stable one. I tried a small OC on the card and my CPU to see if everything is stable, and it seems to be. Max draw on the GPU tops out at around 250 W, iirc, with a minor overclock, and it runs consistently at around 2K MHz (memory bumped up to 7 500 as well). CPU draws around 120 W @ 4.3 GHz.