I have a circa 2008 iMac which is starting to show its age, just a tad. I'm considering purchasing additional RAM. Currently, there is 1GB of 667 MHz DDR2 SDRAM in the machine. I was going to pick up 2 2GB sticks of 667MHz RAM when I noticed that I have a bus speed of 800MHz. Honestly, I'm not entirely sure if that has any relevance. But I was curious if I should go ahead with the 667, or whether I'd be better off with 800Mhz RAM instead. Thanks in advance for your help.