Hi, I want to upgrade from 2x2gb to 2x4gb ram in my 2.3Ghz 13'' 2011 Macbook pro. I've read something about 1333 being wrong but the reccomended spec for the ram, using the website checker is as follows DDR3 PC3-10600 CL=9 Unbuffered NON-ECC DDR3-1333 1.5V 512Meg x 64 Is this wrong then? Im guessing it's the DDR3-1333 people are talking about, however I can't seem to find the speed people suggest (1066?). I'm using mrmemory.co.uk and crucial.com/uk. Any advice would be really apreciated. Thanks Almost forgot. I also want to upgrade my Imac, which is a 27'' 3.2ghz mid 2010 from 2x2gb by adding 2x4gb making it 12gb. is this ok to do? If so are the following reccomended (by Crucual.com) ok? DDR3 PC3-10600 CL=9 Unbuffered NON-ECC DDR3-1333 1.35V 256Meg x 64 edit AGAIN, Just checked and apple ship the macbook pros with ddr3-1333, have I got the complete wrong end of the stick?