HardOCP looked at the performance of some retail systems with a Windows Vista Capable badge:
If you haven’t heard, Windows Vista will be the next major Windows operating system to come out of Redmond, Washington-based Microsoft Corporation. Vista brings all sorts of visual and interface enhancements (not to mention the “behind-the-scenes” stuff like DirectX 10) that are shaping up to require quite a bit more hardware muscle to power. Indeed, the minimum specifications are much beefier than those for Windows XP. In particular, the new “Aero” graphical user interface will require the power of a modern DirectX 9 video card with 128MB of RAM. Those wanting to run at very high resolutions will have to have a video card with 256MB of RAM.