I have an early 2008 24" iMac with two sticks of memory, 2gb, each, in my two slots. I'm confused, I've read conflicting reports, can I put 4gb of memory in one of my slots, and will it work, or will it just recognize it and not actually increase my RAM. any information would be appreciated. if it's possible, do i put the 4gb in the first slot? and what brand/type of memory do i buy. thanks for your help, i appreciate it!