I was very lucky one week and had 2 iMacs show up at my house (not mine, but borrowing them). One is an iMac DV+ Ruby with a 450 G3, 20GB HD, and 64MB of RAM (which I upgraded to 192 with a 128 DIMM I had lying around) and the other is an iMac G4 700 with a Combo drive, 40GB HD, and 256MB of RAM. I am looking to upgrade the RAM in both machines, as the Ruby is in use by my sister as her primary machine and the iMac is damn cool. I have two questions: How much RAM should I put in each machine? Both are running OS 10.2.4. I am thinking I should buy a 512MB DIMM for the Ruby since it would be $41 and a 256MB SODIMM for the G4 since that would be $29. Also, can I use PC133 memory in the Ruby? I tried a 256MB DIMM (left over from when I had PC133 RAM in my PC) and it didn't work (machine would not boot). Thanks.