Guys I think I've figured out how to fly F-18 without AA slowdown on a fairly recent Win10 hardware. I'm using latest version of DxWnd along with my config file. All I can say is that if you limit your resolution to 1028x768 you wont experience any AA slowdown. Any increase from that resolution induces the frame rate drop the moment you go into AA.

Core i7 10700KF, MSI Z490 MEG UNIFY, 32GB DDR4 RAM, RTX 2080 Super 8GB, 1 TB SAMSUNG NVMe x 1, 4TB Seagate SATA3 x 2, CORSAIR RM850x PSU, Thrustmaster HOTAS Warthog, Track IR 4 and Oculus Rift S.