A big thanks to all here answering my questions about memory upgrades. Finally bit the bullet and ordered from OWC the 1gb memory module for my PB 12 "rev B. Could not be happier! I had 512mb before, and some quick tests after the FedEx guy left, and having 1.2gb memory does make a difference with my Adobe CS package. System does seem snappier even before the 10.3.4 update. Words of advice to those that are wondering if going to 1gb of RAM is worth it, DO IT! You won't regret it.