I\'m using rails Version 3.0.3 and ruby Version 1.9.2p136 (2010-12-15) on a Intel Core 2 Duo 2,6 Ghz with 4 GB Ram and Windows Vista Business SP2 with no other (heavy) appli
It is faster to use Ruby inside an Ubuntu Virtual Machine than using it directly with Windows.
A good option is to use Vagrant: You develop on your Windows IDE, and files are "shared" with the Ubuntu VM, you run "vagrant ssh", then run "rails server", or any other command you'd like to run. There are other benefits as well:
Take a look: http://www.vagrantup.com/