Ok, so I know memory has to be installed in pairs. I'm trying to do that, but it's not recognizing all of my memory. So I'm trying to figure out where I went wrong (which I surely did). I have a mac pro, little over a year old. I had the 2GB standard memory installed. So I bought 8GB more (4 x 2GB sticks). I tried following the manual. I ended up with two pairs on top (basically all four 2GB sticks) and one pair on bottom (two 1GB sticks). This seemed to be what the manual said. Two pairs on top and one pair on bottom for 6 sticks. But it only seems to be recognizing 8GB now. Where did I go wrong? I need help!?!