this upgrade is targeted at people who hate vista.
it has also been put into place so that the turnover over desktops/laptop pre new OS release does not slow, as it does with every release.
without lookin at your machine i'd say there is something wrong with it, none of my machines are thaty high spec and i run vista on em.My machine has 8gb of ram Q6850 CPU and vista still runs like a dog.
the slowest being a 1.8 dual core, 2gb ram