Two S1070s on a single Win 2008 R2 node? Win 2008R2 will boot with 2,4,6 GPUs but not 8

I have four of the NVidia interface cards in a Windows 2008 R2 server. If I connect 3 of the cables, the system boots, and all sixe GPUs are active. If I connect all four cables, the system stops after the Windows status bar.

I have disabled the onboard NIC, RAID and any other PCIe devices. Neither the 197.03 or 197.45 drivers will work.

This used to work with Windows 2008 server.

Any ideas?

Sorry about the double post. I didn’t think I posted to GPU area last night.