Hi, new to this site. I have an iMac (all white) from 2006 with the following specs: iMac5,1 ; 2.16 GHz Intel Core 2 Duo; 1 GB 667 MHz DDR2 SDRAM; L2 Cache 4 MB ; Storage capacity 319.73 GB, available 228.39 GB. Currently running Snow Leopard 10.6.8. Just ordered 4 GB memory from OWC, will install once received. I understand my iMac's capacity is 3GB, but also read that going with two 2GB drives is better than a 2GB and 1GB, and might actually give a little more than 3GB. Once I do this (hopefully successfully) I would be interested in upgrading the OS. Given my limitations, should I go to Lion, Mountain Lion, or even Yosemite? I saw where Yosemite requires 2 GB, so I'll have that - but guess I'm looking for the best combination of newer OS / performance given my limited memory. I don't run too much on my computer, basically light word processing and internet - not much streaming / downloading right now, although streaming may increase at some point. Thanks a lot for any suggestions !