Which motherboard(s) can fit 2 Intel Xenon Nehalem CPUs (ideally W5580) & 4 Tesla C1060?
Has anyone tested them?
As far as I know there aren’t any motherboards out yet that support such a configuration.
Perhaps something like the new two-CPU Mac Pro can work for you. It does have 4 PCI-Express slots, but I believe they are single-width … that precludes the C1060 cards, but maybe you can make use of the breakout-box-style Teslas.
The whole Mac Pro package may not be useful to you, but there’s probably a similar motherboard available commercially somewhere. Hope this hint is useful!
I don’t believe there is an EFI version of the C1060, so an Apple board is probably out of the question at this stage.
What is a breakout-box-style Tesla?
Is there any support for the S1070 on OS X? I assume it will have the same BIOS issues as using normal PC video cards in OS X. (Of course, one could buy a Mac Pro, and use Bootcamp to install Ubuntu or RHEL on it instead of OS X.)
Not presently, no.