I have an ASrock Z97X Fatal1ty Killer (great board btw) and I currently have 2 x 4 Gb G.Skill Ripjaws X 1600 Mhz. I would like to add more ram and wondering if I can do 2 x 8 Gb sticks and 2x 4 Gb sticks. Also would I need to take out the motherboard from my build and unplug the computer to install it or can I keep it plugged in but shutdown and the motherboard in the PC. Can I also mix up the ram brands such as having G.Skill and Corsair ram in the same rig and what happens if I have a 1600 Mhz ram and 1866 ram in my build?