Adobe has a live presentation & Q&A on Optimizing Performance for Production Premium CS5, scheduled on January 24, Noon PST. You have to sign up on Facebook for now.
If you can’t wait for this, check out Setting Up After Effects for Optimum Performance on AE Portal. Here’s Setting Up After Effects for Optimum Performance with 64-Bit Systems by Todd Kopriva from Adobe After Effects CS5: Learn by Video: