Upgrading my sister's Mid-2010 MBP 13" MacBookPro7,1 MC374LL/A. I bought this RAM: http://www.frys.com/product/7912890 Its DDR3 and laptop is DDR3. The laptop just beeps when you turn it on with the RAM installed. I tried each module individually in each memory slot. Any guesses as to why its incompatible?