Just found this online, not sure if many people these days still know about it, but here it is anyway for those interested. Was doing a search for tasks running in my task manager to find out which ones are safe to shut off for a little system boost to help out while gaming. Ran across the following that I had forgotten about over the years. Damn visual effects are just so appealing these days, but you'd be surprised at what the price your system pays to show it.

DWM uses a lot of memory and CPU usage in Vista however you do not have to end it in order for it to stop using memory. You can simply shut down a lot of the processes that the DWM file is using. Click on the start button, right click on computer and choose properties. Click on the Advanced System Settings link to the left; this will bring up the System properties window with the Advanced Tab chosen. On the Advanced Tab there is 3 boxed areas; Performance, User Profiles and Startup and Recovery. From the Performance boxed area click Settings. Uncheck any boxes on Visual Effects tab.
DWM.exe is a Windows file that runs at all times unless deactivated. This is what makes all the windows and system effects so appealing to the eye. Follow this step and you can have that oldschool look and feel and things on your computer will run smoother and a bit faster. Hope this helps out some of you. Also, if this file is found in any other location than in the %systemroot%\System32 folder, it is a virus. This should be the only one in your computer.