I have a gigabyte EP45-UD3P board that I have been running Snow Leopard on for a while now. I had only a pair of 1gig sticks of ram in the machine. I figured I would up the performance of the machine and get 4 x 4GB sticks of ram to fill it up. The machine will not finish loading with all 4 sticks of ram in the machine, it will get to the loading page with an Apple and a spinning loading icon. If I put in only 1 pair everything loads fine, I have tried it with either set of 4 GB and the pair of 1GB sticks and it will not load. It seems that it will not load with 4 sticks of RAM in it?????