I have a BTO 21.5" 3.6GHZ i5 iMac on the way with the stock 4 GB RAM. I have 2 2GB DDR3 PC3-8500 sticks from when I upgraded to 8GB in my 17" MacBook Pro. Will I be able to add these to my new iMac? Will I see any performance hit, or just not realize a performance gain by adding PC3-8500 instead of DDR3 PC3-10600 RAM? At some point (3-6 months+) would probably sell the PC3-8500 sticks, along with the stock iMac RAM to upgrade to 12+ GB.... so I'm fine not even using the extra 8500 sticks now.