I am using a new Gigabyte GA-990FXA-UD3 motherboard with an AMD Phenom II x4 965 cpu. I originally only had a single 8GB stick of DDR3 1600Mhz which worked fine, but to upgrade that I only had 4x2GB DDR3 1600Mhz sticks. So the current setup starting at the slot closest to the cpu is 8gb, 2gb, 2gb, 2gb. The only thing I can think of that is causing this is the dual-channel mode failing to utilize the extra space because of the difference in capacity of the sticks. I don't know if it makes a difference but I am using a 64GB SSD as the root drive that only has 12GB available space which limits the paging file size for virtual ram. I have tried re-seating the RAM, taking the CMOS battery out, checking for BIOS updates/RAM settings, and checking msconfig boot to make sure It wasn't limiting anything. Any help on this issue would be greatly appreciated.