[costan]

I wouldn't expect performance to be a problem. For computational tasks, Ruby works just as fine on Windows as on a UNIX platform.

Windows perf suffers because (1) in some rare cases, the needed primitives aren't provided by the kernel, and (2) Windows does some things differently, and Ruby library authors don't have the incentives to design and maintain a separate codepath for Windows.

The issues above don't usually arise in desktop applications. They're seen most often in server code -- fork is missing and that sucks, asynchronous I/O works differently, file monitoring and pipes also work differently, etc.