Windows HPC Server 2008 supports InfiniBand interconnect. Nothing new here. We use InfiniBand in our lab here on the Microsoft main campus in Redmond, WA. It's time for an upgrade of the existing InfiniBand hardware. Now you would think, Microsoft, they just go and buy the latest and greatest and give a damn about cost. Far from true. In our quest for a reasonably priced solution Giovanni found an article "InfiniBand for the Masses" on ClusterMonkey:

"Mellanox and Colfax International have teamed up to bring back SDR but at a price point that makes it extremely attractive for small clusters. At this point you're saying "Shut up and tell me the prices!" As I tell my children, "Just relax" but I usually end up with something thrown in my general direction. Since I don't want anyone to thrown things at me, let's go over the prices. BTW - the website with all of the prices is here."

We'll do some more investigation but this looks irresistible to me.