Hi guys, I have an Mac mini mid 2012 with 4gb of RAM (2x 2gb cards). I was thinking about purchasing the Crucial 8gb upgrade kit (2x 4gb cards). However I noticed that I could purchase one 8gb card, and only replace one of the 2gb cards in the Mac mini making 10gb in total. I know you can mix RAM sizes however Apple's website says that you shouldn't mix RAM sizes for optimum performance. My question is which would be better. just purchasing a 8gb card, and having 10gb in total but them not running at 'optimum performance' or replacing both with the 8gb kit and only having 8gb in total. Thanks in advance for your help.