Hello, I am trying to upgrade my wife's memory on her G4 PowerMac 400 Mhz. She has at present 128MB RAM via 1 SDRAM module. Some (mac newbie) questions: 1. Should I buy the memory at the Apple store? 2. Are there any pairing restrictions? (Can I simply add a 256 module to get 384 - sometimes you can't do this on a PC) Also - is there a way to get into the bios to do any overclocking? I've read you can, but I'm not sure what the interface is to do so on the mac... Thanks!