It is maybe 95% of native performance or in that ballpark, according to benchmarks I've seen.
I have a dedicated M2 disk that I pass thru fully to the Windows VM in order to have snappy disk, and I reserved 64 GB ram to that VM alone using hugepages (because I multibox a old game that requires lots of RAM for my use case).
I also pass thru the bluetooth hardware into the VM as I don't use bluetooth on my host, so that I can use my dualsense controller while gaming in the VM.
