I have upgraded my 1.25GHz iMac's G4 RAM from 512MB to 1.5GB. It was running Tiger. It was quite slow with 512MB of RAM, but I saw on this forum someone said that 1.5GB run Tiger flawlessly. Well, it haven't boosted AT ALL. 1.5GB is 3x more memory than 512MB, so it's supposed to be faster. It was still laggy, and I think it got slightly worse. iShowU recording was very laggy with 512MB but it freezes my computer and I am lucky if I manage to stop the video with 1.5GB of RAM. Can't even watch 480p videos. iMovie lags while previewing video, and the list goes on. G4 is supposed to be a powerful machine, but not mine. I upgraded to Leopard, nothing really changed. Can somebody explain it to me?