Microsoft has offered the Windows Vista Upgrade Advisor for the past several months, which essentially rates your computer's performance, recommends a specific edition, and highlights any major caveats in your system before upgrading. There is also this online test from ATI/AMD, which I consider to be slightly superior to the Microsoft offering. Just keep in mind that neither is foolproof, so you may encounter difficulties/incompatibilities that neither test foretold. If such occurs, we're here to help.
Good luck.
John
I have XP and am thinking about upgrading to Vista Home Premium. I know there is a scale in Vista out of 5 that shows where your PC ranks in peformance. I want to know what my score would be before I upgrade so I can make any hardware upgrades before installing. Is there a way I could check this in XP? A download? Thanks.

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