not all video card chipsets are supported
taken from the windows vista site:
A Windows Vista Capable PC includes at least:
A modern processor (at least 800MHz
1).
512 MB of system memory.
A graphics processor that is DirectX 9 capable
A Windows Vista Premium Ready PC includes at least:
1 GHz 32-bit (x86) or 64-bit (x64) processor
1.
1 GB of system memory.
A graphics processor that runs Windows Aero
2.
128 MB of graphics memory.
40 GB of hard drive capacity with 15 GB free space.
DVD-ROM Drive
3.
Audio output capability.
Internet access capability.
Windows Vista Capable and Premium Ready footnotes
Processor speed is specified as the nominal operational processor frequency for the device. Some processors have power management which allows the processor to run at lower rate to save power.
Windows Aero requires:
DirectX 9 class graphics processor that:
Supports a WDDM Driver.
Supports Pixel Shader 2.0 in hardware.
Supports 32 bits per pixel.
Adequate graphics memory.
64 MB of graphics memory to support a single monitor less than 1,310,720 pixels
128 MB of graphics memory to support a single monitor at resolutions from 1,310,720 to 2,304,000 pixels
256 MB of graphics memory to support a single monitor at resolutions higher than 2,304,000 pixels
Meets graphics memory bandwidth requirements, as assessed by Windows Vista Upgrade Advisor running on Windows XP
A DVD-ROM may be external (not integral, not built into the system).
Can the Windows Vista experience vary on different PCs?
Yes. Windows Vista is the first Windows operating system with a user experience that adapts to take advantage of the capabilities of the hardware on which it is installed.
All Windows Vista Capable PCs will be able to run at least the core experiences of Windows Vista.
All Windows Vista Premium Ready PCs can deliver even better Windows Vista experiences, including the new Windows Aero user experience.
Does buying a Windows Vista Capable PC mean that I will receive a free upgrade to Windows Vista?
No. A PC that is Windows Vista Capable or Premium Ready means that the PC is ready for an upgrade from Windows XP. You would still need to purchase the edition of Windows Vista that you want to install on your Windows Vista Capable or Premium Ready PC.