Vista Tips - Enabling Aero Glass on Slower Hardware

Aero Glass can be resource intensive depending on your CPU, amount of RAM, and screen resolution. On top of the speed of your hardware, the DWM (Desktop Window Manager) has strict hardware requirements, such as a video card that supports DirectX 9 hardware acceleration and Pixel Shader 2.0 support. It also requires new Windows Vista WDDM (Windows display driver model) video drivers to function.

Failure to meet the hardware and driver requirements will result in no Glass for you. Back in the beta days, you could trick the DWM into running Glass in a software Direct3D emulation mode and bypassing the hardware checks. This made it possible to run Glass, but so poorly that the operating system was pretty much useless because the frame rate was less than one frame per second. In the final version of Windows Vista, that support was yanked, so you are left with the task of meeting the hardware and driver requirements to run Glass.

Say you have a computer that has a DirectX 9 accelerated graphics card with Pixel Shader 2.0 support and are running WDDM drivers for your card. Aero Glass is going to run, right? Not exactly. The first time that you boot your computer after Windows Vista is installed, Windows will benchmark your computer and all its hardware components during its initial hardware assessment.

Based on the results of this benchmark, it automatically fine-tunes Vista settings so that it performs the best on your hardware; atleast that's its goal. If hardware assessment finds any thresholds not met, such as not enough RAM, it disables Aero Glass from running on your computer even if your hardware can technically support it.

What are you to do?
With the help of a useful tweak I show you in this section, you can override the decision and re-enable Aero Glass. If you fall into this situation, I have good news for you. Many users have found that after they override the setting and re-enable Aero Glass, their system performance is just fine. It seems that the Windows hardware assessment might be a little too strict when it comes to deciding whether Aero Glass should be disabled.

Overriding the Windows decision to disable Aero Glass is easy via Registry Editor. Follow these steps to re-enable Aero Glass on your computer:

1. Click the Start button, type regedit, and press Enter.
2. When Registry Editor has opened, navigate to
   • HKEY_CURRENT_USER\Software\ Microsoft\Windows\DWM
   
   Working with the Registry to enable Aero Glass
   
   
3. Right-click on Composition and select Modify.
4. Set the value to 1 and press OK.
5. Right-click CompositionPolicy and select Modify.
6. Set the value to 2 and press OK.
7. Close Registry Editor and restart your computer.
   You can restart the service by typing net stop uxsms followed by net start uxsms at an administrative-level command prompt.

After you set the two Registry values and restart the service or your computer, you will immediately see Aero Glass running if your hardware truly supports it and you have WDDM drivers for your video card.