Parallels - run Windows on a Mac
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The killer app for Mac is now even better than ever!
Parallels Desktop for Mac enables you to run Windows, Linux, and more side-by-side with Mac OS X on any Intel-powered Mac, without rebooting. With Parallels’ award-winning virtualization technology, you can run Mac OS X and your favorite Windows applications at the same time. You can even drag-and-drop files between desktops!
Parallels is a "virtual machine" which runs on the Mac partition. This allows you to run Mac and Windows both at the same time. Theoretically a virtual machine is not as fast as the real machine. We tested Parallels (unscientifically) without any noticeable reduction in performance in resource demanding 1st person shooter multiplayer games. Parallels is a clear winner, giving the boot to Boot Camp.