I'll soon be getting a working G4 400 AGP Gigabit Ethernet Mac. I can also get a processor card from a G4 533 AGP Digital Audio Mac very cheaply. Can I simply upgrade the 400 Mhz processor card with the 533 Mhz one? Both are NOT dual processor units. I do know the bus speeds are different but will this work or do I need to change something else? Thank-you.