I run 3d modelling (Lightwave), graphics (ImageFX) and music recording stuff on it. RTG is a must for me, and it runs really well under with the WinUAE setup.
There's a major bug in FS-UAE where it suffers from slowdowns under these exact circumstances. The author isn't using RTG himself, so it went unnoticed for a while.
Check the FS-UAE threads on EAB, they were trying to narrow it down a while ago. I don't know what the current status is.
