I've just purchased a 27" i7 iMac along with an extra 8GB of RAM from Crucial. Everything works perfectly in OS X, but I have been having a few issues with Windows 7 64-bit on Bootcamp. To begin with, the Windows installation process was failing during the "Expanding Files" phase - after some Google searching I found that that a potential fix was to remove extra RAM. I removed the extra 8GB and then Windows installed properly. I then re-inserted the RAM and to begin with everything was fine in Windows - downloaded and installed all the updates, installed Chrome, web browsing okay. However, I then tried installing two completely different pieces of software (one from a CD, one from a downloaded file, both of which I've used before) and both installations failed with a Cyclic Redundancy Check error - which generally points to faulty RAM. I ran the extended Apple Hardware Test from the OS X install disc and no problems were found. And as I say, OS X has been perfectly fine, the only problems have been with Windows. Before I remove the extra RAM and send it back to Crucial, I'd like to check: Could the arrangement of RAM modules in the 4 slots make any difference to Windows? At the moment I have the original 2GB sticks in the first two slots and the 4GB sticks in the second slots. If I reversed them, could this make any difference, or is the RAM just faulty? Thanks in advance, and apologies for the long post!