Wow, I have been too busy to get back to this since April. Just to respond to the comment about the machine I was using... Dell has continued to update that model along the way. This machine was purchased in December 2007 - not 5 years ago, it IS a quad core, and has 4GB of RAM, and runs XP Pro 32bit. That said, let me close this topic out. My problems were solved through another question posted around that same time. It turns out my AE was only accessing 2GB of the RAM until some wise and kind soul shared the deep secret of increasing XP Pro's memory access from the default of 2GB to the max of 3GB.
This solved all my rendering issues, well nearly all. You see AE divides up the available RAM to each core. So while those extra cores are speeding the render up they are fighting for RAM. In an effect heavy HD comp with blurring, BCC effects, 3D, and lights I still have to pre-render here and there. Fortunately not very often.
My advice is to buy a Mac (since I can't see using Vista.) The OS allows AE to access 4GB of RAM. The biggest eye-opener for me was that even if you have 10GB of RAM After Effects will never use more than 3 on Windows and 4 on Mac. So save your money if you're buying extra RAM for AE.
http://forums.creativecow.net/readpost/2/867951
