Here is why. WWW Link

Q5: Why doesn’t the Intel 915 Express chipset family support Windows Vista Aero?

A5: The overall graphics architecture and design of the 915 Express chipset family (with Intel® Graphics Media Accelerator 900 graphics engine) was finalized prior to Microsoft releasing details and specifications around the Windows Display Driver Model (WDDM) driver. Given this, there are hardware limitations in the 915 Express chipset architecture that would limit graphics performance and memory capabilities when attempting to run WDDM on Vista.

The hardware limitations of 915/GMA900 graphics center around not having a large enough memory table to support Vista Aero, a key feature that is part of WDDM driver support. This, along with hardware restrictions on surface placement and graphics memory alignment, results in graphics memory usage that is not optimized for Aero performance. Additionally, the lack of native hardware support in the 915 Express chipset family for Vista’s dynamic memory management would result in slower graphics performance and a sub-optimal user experience with Windows Vista Aero.

With these identified limitations, the 915/GMA900-based graphics system would not have met the performance requirements for Aero desktop composition support under Vista. This ultimately led to the decision to begin WDDM support with the Intel 945 Express chipset products, as Intel addressed these hardware limitations with the desktop and mobile Intel 945 Express chipset families.

To provide the best performance and user experience with Windows Vista on Intel 915/GMA900 platforms, Intel will support Windows Vista on 915/GMA900 with the drivers based on the XP driver model.

I'm running Windows XP Pro SP2 with the latest WB 6 loaded. I ran into the problem of the Start Menu and Window Frames not having transparency applied when logging into my account. If I set the transparency for these items and hit "Apply Changes", they would go transparent. But, after logging out and back on, only the task bar would be transparent. I have only been able to have the Start Menu and Window Frames go transparent if I put WBLoad in the Startup folder (in the programs menu). Of course this means I have to wait for WB to reload each time I log on. A little annoying, but I live with it. Normally, each time I logged in, WB would load and the icon would show up in the system tray, but these items would not go transparent. Only if I placed WBLoad in the startup folder could I force these items to go transparent. If there is an issue I am missing that would allow these items to go transparent with a normal log in without having to reload WB from the Startup folder each time, it would be greta if someone could share it with me. Thanks, Bill Edwards