Here is my current machines Score.

You can find out the score of your machine before installing Vista by going to the Vista Upgrade Advisor Page and download the Advisor. It will evaluate your computers hardware and give you a Score.

Don’t upgrade unless your machine is at least a 3.0. 2.9 and lower you won’t get the Vista Experience.

Vista Launch Day: Grade your PC’s Vista capabilities

My Vista notebook’s a lowly 2.2 compared to Gizmodo’s 3.7. Kind of a like a GPA for your PC’s hardware and it’s ability to handle the Vista monster, Gizmodo’s Jason Chen interprets the “Windows Experience Index” numeric scale:

A 1 means you should just seriously go back to XP. Microsoft wants your money, but not that badly. A score of 2 is the basic score you’ll need to do anything on Vista worth while. A 3 (which is what we have, a high 3) is going to be the “value end”, or super cheap, PCs being shipped into 2007. A 4 is a mid-range machine, and a 5 is a high-end monster that can do Aero-Glass on multiple monitors and hack into the Matrix.

What would be nice is to see these numbers before you install Vista, but for new upgraders it’s a useful place to see your machine’s weakest spot. (Your score is based on the lowest one in the group, not the average.) What’s your computer’s Vista score? Get it in Control Panel, System and Maintenance and let us know in the comments. — Gina Trapani

Source: Vista Launch Day: Grade your PC’s Vista capabilities – Lifehacker