Later versions of WinUAE are definitely slower for emulating classic games, demos and the like. It's supposed to be more accurate too, but I haven't seen much practical benefit. If you have a slow computer, I would advise you to find version 0.8.8. This gives a damn-near flawless Amiga emulation on a 1999-vintage 400Mhz PII with 64 megs of RAM running Windows 98 and still works perfectly on a modern machine under XP. It's extremely stable too, unlike some of the glitchy updates I've tried since.