Windows only: Free, open-source application Halite is a BitTorrent client with a focus on a small memory footprint. With Halite running and actively downloading on my system, I never saw the memory usage crest 10MB of RAM—which, as BitTorrent weblog TorrentFreak points out, is about half the memory consumption of the popular-for-its-small-footprint uTorrent. Granted, Halite doesn't have near the advanced features of uTorrent, but it does support most basic features, like encryption and selective file downloading. If all you want is a no-nonsense BitTorrent client that can grab your downloads with the best of them, Halite may be just what you need. Halite is free, Windows only.