lol. theres a major bug in vista when using dual core cpus with agp graphics. It either wont install the graphics card or you have to uninstall a cpu core. Beleive me if there was a solution I would be on vista. Its not about the computer speed its about the bugs.
I've had (actually got rid of them last week) 2 computers with dual core and AGP with Vista Ultimate. Both worked flawlessly and had done since Vista RTM was available.