CS5 will be the first 64-bit version of After Effects.
Photoshop CS4 is 64-bit, which is why it installed in the appropriate directory on your OS.
Thanks for the link...
". This means that after 3 versions of supporting both 64- and 32-bit, the next version of After Effects will only support 64-bit operating systems."
So are you 100% positive that CS4 is 32 bit except for Photoshop which is 64 bit.
Moving on... what roll does getting one of there suggested high end video cards. I'm looking at the NVIDIA Quadro® FX 3800. I was looking at this page, http://www.adobe.com/products/creativesuite/production/performance/
Yes, After Effects CS4 is a 32-bit application. The next major version will be a 64-bit application.
Don't confuse these statements with statements about whether the operating systems on which the application can run are 32-bit or 64-bit.
After Effects CS4 runs on several 64-bit operating systems and on several 32-bit operating systems. The next major version of After Effects will only run on 64-bit operating systems. And it will be a 64-bit application.