I just upgraded my ram from 2 Gb to 2X2 gb Ram. I bought the Crucial 2 X 2GB, DDR3pc3, 8500 CL7, 204 - Pin Sodimm 256MX64 1066 MHz. After installing it I checked in open system profiler if my mbp recognizes my new memory, it did. The only difference is that I have 1067 MHz instead of 1066. Since I read in the Mac Manual that I need to get a 1066 MHz I ordered this one, but I got the 1067 instead. What is the difference between the two? It won't do any harm, does it? I am sorry, maybe it's a dumb question, but I don't know anything about computers and it's the first time that I opened one. I also have another question. I ordered mine through Ebay and I wanted to check if my memory is really Crucial memory. But when I look in system profiler I can see that manufacturer is 0x0d9B, part number and serial number is 0x000000000 etc. Shouldn't there by stated Crucial at manufacturer and a part number and serial number instead of all those zero's? I also upgraded my hdd, I put Hitachi 5400 rpm 500 gb in it. I am very happy with it, the laptop is supersilent and until now it runs smoothly. First I was thinking of getting a Seagate 500 gb 7200 rpm,m but after reading quite some negative reviews I decided to go for the Hitachi. Thank you so much in advance for answering my questions!