Q: In Task Manager, a program called ‘dwm.exe’ is consuming a lot of memory. What is it, and why does it take so much of my system’s memory?

A: dwm.exe (which stands for Desktop Window Manager, in case you didn’t know) is the Windows process that serves up all of newer versions of Windows cool effects such as taskbar thumbnails and Flip 3D, which can be activated by pressing Windows+Tab.

dwm.exe runs because Windows Vista (or newer) is keeping track of what is happening on each window that you have open on your computer. This is so Vista can present effects such as Flip 3D with such speed. However, the process can take up a significant proportion of your system memory, and if your computer does not incorporate the latest technology, may even slow your system down. To see how much memory dwm.exe is taking up on your computer, hit Ctrl+Alt+Delete, click Start Task Manager, Processes, and scroll down to dwm.exe. On my computer the process consumed 19 MB of memory, but on yours the figure may be higher.

Turning off dwm.exe won’t do that much to speed up your computer, but it might help a little. Switching to Vista Basic mode won’t completely fix the issue, merely fix its effects. If your heart is set on temporarily stopping the Desktop Window Manager process, click Start, Control Panel, type ‘services’ in the Control Panel search box in the top right-hand corner of your screen and select Local Services. Scroll down to Desktop Window Manager Session Manager, click it, and click Stop the service. Your system will be set to the Windows Vista Basic color scheme and features such as Flip 3D won’t work (although Alt-Tab still will). If you would like to start the service again, navigate back to the services interface.

It is important to note that Desktop Window Manager still appears in Windows 7, and the same process may be followed to stop the service. The ‘basic’ color scheme will reappear on Windows 7 if you disable Desktop Window Manager, so if you value Windows 7’s sleek interfaces, this might not be a good idea!

If you dislike Desktop Window Manager enough to permanently disable it, it is possible to stop the process from opening on start up. To do this, head back to the Local Services interface and double-click Desktop Window Manager Session Manager again. Under ‘Startup type’, choose Disabled from the drop-down menu. Hit Apply and you’ll never be plagued by dwm.exe again!