Hi,
Without much details,
With Vault what you can do is to store your project files and keep track on file revisions.
With Productstream you're able to, besides the vaulting, keep track on your products lifecycle - it's a PLM.
When thinking of implementing ADMS (wich is the server application for both Vault/Producstream) a dedicated server is what you would want. No need to be using memory from a workstation with SQL, and besides it should be prepared for running all the time to work on backup's, maintaining your DB, so on. you can get an idea for the HW required in your Inventor papers that come with the DVD's.
Think of it as a server, as anyother server. It's a SQL server before all.
Hope it helps a little bit,
David