Nout, the answer to your question which I have concocted goes along the following lines. DM uses low-level-ish UNIX-y things to do the desktop switching. These don't require much memory. OS X, being built on the UNIX-y stuff, recognizes that it doesn't have to calculate the drawing crap for all the unseen background windows. As long as you're not using Apple's latest super-dee-duper graphics technology and a recent graphics card, this takes some weight off of the CPU, thus giving Safari more thinky time.<br><br>Following that rather-lengthy-for-a-VT-comment review, here's my actually comment on the actual product, which I have been using for some months now:<br><br>Try it or else I will beat you with a large spiky stick.<br><br>It increases productivity by decreasing visual clutter, gives actual computer speed a tiny boost, has just enough settings for me to tweak, works flawlessly, is open source, and looks good to boot. Props to the developer for making such an incredible piece of awesomeness.