4x Titan gives invalid device ordinal, 1x Titan is fine

I am setting up a new system with ubuntu 12.04, ivy bridge CPUs, four GTX Titans, and CUDA-5.5. I currently have the system plugged into 110 V power supply, but it will get moved to 208 V. When only one Titan is on the board it checks out fine with .deviceQuery. When I have two or more Titans on board .deviceQuery returns

cudaGetDeviceCount returned 10
-> invalid device ordinal
Result = FAIL

lspci | grep NVIDIA shows that all the Titans are present

the cards are present in /dev (in this case two Titans on board)
crw-rw-rw 1 root root 195, 0 Dec 3 16:23 /dev/nvidia0
crw-rw-rw 1 root root 195, 1 Dec 3 16:23 /dev/nvidia1
crw-rw-rw 1 root root 195, 255 Dec 3 16:23 /dev/nvidia0

When I had four Titans on board only two showed up in nvidia-settings. Now, with two on board and after re-installing the driver (319.37) and cuda-5.5 toolkit, only one Titan shows up in nvidia-settings.

I will greatly appreciate any assistance resolving this issue.