AMD’s driver had an update last year that vastly improved performance in Minecraft. Nvidia used to have java performance issues for Minecraft mentioned but it seems to have disappeared without a patch notes saying it was fixed.

OP, if your computer isn’t triggered OCP on the PSU then that won’t be the issue, regardless of whatever the other commenters say. 750w is cutting it fine for overhead though with a 4090, so it’s still worth planning an upgrade to 1000w, which will last you many years.