I do some photoshop work at home (wedding album design, average file size 150 Mb). Currently my fastest machine is 15"PB G4 1.5Ghz with 1.5Gb Ram. Its painfully slow. Should I invest another $150 to increase Ram to 2Gb (will have to sell 512Mb later) or put that money aside for an iMac purchase in near future. Suggestions are greatly appreciated. P.S. Does anyone has experience with a similar upgrade and its effect on PhotoShop performance with large files.