So, one of the things I knew I was going to do before I even bought my iMac was upgrade the RAM. 4GB isn't bad but that's what my 2 year old MBP came with. According to Apple's guidelines I need to make sure I am buying 1333MHz, PC3-10600, DDR3, unbuffered and unregistered RAM. I've looked over the specs of the 3 candidates here and I can't find a difference. Are these really all exactly the same with different prices? http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=769226C4A5CA7304 http://eshop.macsales.com/item/Other%20World%20Computing/1333DDR3S08S/ http://eshop.macsales.com/item/Newer%20Technology/1333DDR3S08S/ I'm pretty sure that neither OWC nor does NuRAM have their own fab. I guess I have to wonder if Crucial does either. They are most likely slapping their name on some Samsung RAM. I have extensive good experience with Crucial but none with OWC or NuRAM. I like to save money but am I getting something less performance wise by going with OWC or NuRAM? I'm also a little concerned that OWC says "Install Pairs (2 at a time) for best performance". I'm not finding any evidence that my iMac has a dual channel memory configuration which would make this statement true. What do you guys think? Thanks!