Some ignorant hearsay for ya: A memory clerk at Fry's Electronics told me that although many types of PC100 RAM should work with the G4, he's had returns for all types except the highest quality (and price). Sorry, I can't remember the exact spec. He also said that all RAM in the system will sync to the chip with the lowest performance. Based on that, I ordered 256 RAM from Apple with my G4 order. Pay more, worry less: That's the general Apple philosophy, right?