Hi all. I'm wanting to upgradge the ram on my G4 powerbook 1.67GHz and am a bit stuck. It currently has 512MB in one of the slots and in system profiler it reads : SODIMM0/J20STANDARD: Size: 512 MB Type: DDR2 SDRAM Speed: PC2-4200S-444 Status: OK I wish to install another 1GB on top of that. I have gone through all of the steps on Crucial.com for finding the appropriate ram for my computer. on the page ( http://www.crucial.com/uk/store/lis...k G4 1.67GHz (15-inch Display) DDR2&submit=Go ) there are two options for 1GB chips. Would either of them be incompatable with the exisiting chip I have, or would it be advisable to get one over the other? How they differ is one is DDR2 PC2-4200, the other DDR2 PC2-5300, and one is DDR2-533, while the other is DDR2-667. They are only £10 different in price so I'll get whichever one is faster. Thanks!