There’s two reasons that the current OS X version of After Effects is slower:
1. The code generated by Apple’s compiler is not quite as fast as the Windows compilers that Adobe uses.
2. Windows XP has been around for years, so the Windows-specific AE code has been more optimized over the years than the brand-new Intel-Mac-specific code.
I’d expect both things to improve in the future: Apple’s Xcode will become faster and Adobe will have more time to optimize the platform-specific Mac code. Another benefit of Apple’s switch to Intel hardware is that the Intel-specific optimizations can now help both Windows and OS X users of After Effects.
Still, there’s one BIG reason why Windows on Mac hardware isn’t the ultimate solution; that the Apple hardware only gives the 32-bit versions of XP and Vista access to 2 GB of RAM on Macs. The solution is to use Vista64 or XPx64.
Photo by Bekah Stargazing