My A1200 died some time ago. Since then,I have a 2ghz cybernet zpc all in one setup with winuae that boots right to aos3.9.
Its fine for most things, but when I tried really demanding aga games it would sometimes be slow. I lowered the frame rates alot, which honestly I don't notice any difference visually, but now everything works fine.
Its funny that a 2ghz computer is not enough to emulate a 14mhz amiga. That says alot about amigas.
Steven