I was doing some testing of games running on my Mini 10 with Win7 RC and noticed that the framerate kept hiccuping every couple of seconds. I looked in the task manager and saw that the DWM process was using 13-21% of the CPU (and nothing was really going on with the desktop). This process is what gives the cool translucent effects to the various desktop features. If you try to kill the process it will just start again. To disable it, run services.msc and set it to disabled. The loss of functionality on the desktop is not a big deal. I would guess that it also eats battery life, so killing it will probably extend the battery life.