Re: How to make Win7 handle eight GPUs properly ?
I assume this is a computation machine. The link to the server rack mount says it supports 8 GPU's and has adequate power, so I'm not quite sure what the issue is.
You are pushing the RAM limitation on Windows 7 Ultimate x64. Have you considered Windows Server or Linux? I guess it depends on how you are using these GPU's. If you are writing your own code for them in C/C++ (for CUDA) then Linux would be a better choice anyways. If you're using specific Windows software, then I would make sure Windows server would fix the issue before you take the plunge.
EDIT: The more I look at this machine, the more I think you shouldn't be running a consumer version of Windows on it. It needs Windows Server or some other Enterprise software (or just run Linux).