if he had PSU problems before switching to a true rated one, he wouldn't be getting low FPS, he would be getting constant auto restarts, or game crashes
my guess is that guy really has no idea how things work and he just complained about getting low FPS and had someone look at it and that someone changed the PSU AND also tweaked the game settings. so sa pagkakaalam niya PSU talaga ang dahilan ng low FPS niya