Windows rules on the desktop, but if you want serious performance, there's only one choice: Linux.
As The 451 Group captures in a great write-up of the most recent Top500 report of the world's fastest supercomputers, Linux is the default choice for 85 percent of the world's fastest computers. Windows? It can barely scrape together 1 percent market share.
The world's fastest supercomputer, built by IBM, uses the xCAT distributed computing management and provisioning tool, created by Egan Ford (a friend and IBM's supercomputer guru). The good news for Microsoft? It's open source. Microsoft can use it, too!
Of course, Microsoft would have to switch to Linux first, but that's a small sacrifice to be part of the club generating serious performance for customers, right? Right?!? :-)