Hi forum I've been lurking in here for a few year, finally took the time to create a user recently as i bought my first ever iMac in the new Apple store in Hong Kong last thursday. It's a 3.2ghz, 1TB, 675MX with 8GB ram I've ordered 4x8GB ram from Crucial (2x16GB kits). I have an old Macbook Pro (mid 2009) 2.53GHZ Intel Core 2 Duo. Currently has 2x2GB ram. When I upgrade the iMac can I put the 2x4GB ram from that in my old MacBook? Data from Crucial ram recommender: iMac 2012 late kit: Module Size: 16GB kit (8GBx2) Package: 204-pin SODIMM Feature: DDR3 PC3-12800 Specs: DDR3 PC3-12800 CL=11 Unbuffered NON-ECC DDR3-1600 1.35V 1024Meg x 64 MacBook Pro mid 2009 (unibody): Module Size: 8GB Kit (4GBx2) Package: 204-pin SODIMM Feature: DDR3 PC3-8500 Specs: DDR3 PC3-8500 CL=7 Unbuffered NON-ECC DDR3-1066 1.5V 512Meg x 64 So it's the same size, the iMac ram is faster but i guess there able to 'clock' down backward. The obvious difference is the CL-timings and the voltage! Should I try or just forget about and try and see if someone will swap ram with me?