Hello, I'm new to Mac and new to the forum. I just bought a new 2011 27" iMac and the first order of business was to upgrade the RAM. I ordered 8gb of Crucial 204 pin SODIMM, DDR3 PC3-10600 and installed it into the the two open slots and left the original 2 x 2gb sticks in the factory location. Easy enough, took a couple of minutes to install and power up the Mac. I checked to ensure the 12gb was showing up under the "About this Mac" and it showed 12. I started opening items on the dock and Safari, App Store, and iTunes all had kernal panic's and would not open. After a couple attempts to ensure the ram was seated properly I changed locations of the RAM. I swapped the 2x4gb stick with the 2x2gb sticks and now everything is working fine. After researching the issue, I haven't found anything that says the higher capacity RAM has to be in a certain slot. Has anyone had this issue, or is it confirmed that higher capacity ram has to be in a certain slot? Or is it still a possibility the RAM I received is defective?