I'm running 6 gigs on a P55 mobo. I have 2 sticks of 2gb and 2 sticks of 1gb. When I went to remove the 2x 1gb sticks, my computer wouldn't boot. I have 6gb of available memory so all 4 sticks work. From the CPU over, I have it 2121. Should I remove the 2x 1gb sticks and stick the 2gb stick in place of those?