The 10.4 was purchased as combo from Apple Store, 10.4 with MS Office 2005, Macbook 2 GHz Intel Core 2 Duo, 2.5 Gb 533 MHz Ram, 150 Gb hard drive. Originally only 1 Gb Ram, i upgraded one (.5 Gb) to a 2 Gb. Initially for faster speed within SimCity 4, probably helped when I installed Lion 10.7...