For what I know about the Mac Pro line of computers, it has always been said to add ram in matching pairs. The new 2013 Mac Pro comes with (3)4Gb of ram. Ordering from apple.com, I can upgrade to 16GB of ram for about $100 USD. Other World Computing offers a 4GB ram module for like $65. My question is, will there be any system issues if I add the OWC 4GB ram to the apple 12GB configuration? I am speaking of the baseline configuration.