Even then it's really not that much of a hit if you have half-decent hardware, I've kept it on and I think the only issue I saw was launch day BG3 and it would use much more power from the wall than when I turned it off.

Make sure to have Intel VT-x or AMD-V enabled too.

There are now a lot of BIOS flags that you can have set to off by default that'll silently hinder performance.

There's no way in hell to run any relatively modern hypervisor without VT-x or AMD-V. There are other, newer additions that do provide a performance boost (or well, a smaller loss) but yeah, VT-x/AMD-V is the basis.