I am able to manually enable the GPU's, but they show 0 KHs. If I try to use the restart command, they go offline.

How much system memory is needed? I was under the impression that all the mining was on the GPUs and the system ram was just to run the OS. Someone earlier recomended using 8Gb, but I don't understand why that would be needed. The host CPU isn't doing anything but passing packets between the GPUs and the pool or am I wrong?