Upgrading the motherboard from a 1 year old MSI to a new z87-g45 and slotting the memory according to the guide, only channels 3 & 4 work properly. Went from 16gb 4 slots (2x4gb unknown stock memory and 2x4gb Corsair Vengence I bought after market) the bios didnt boot upon startup. Switching slots did nothing until taking out the old stock modules and moving the corsairs to the 3 & 4 positions finally allowed bootup. Dual channel is unresponsive (slots 2 & 4 same no boot up) and even buying a replacement 4gb PNY stick adding to additional slots still no boot up. I can live with 8gb but trying to figure out if I have 2 dead channels on a fresh out of the box motherboard and need to send it back in or Im just setting them up wrong. All DDR3 and running same speed.