I have the preview installed and my lowest is my HDD (my SSD is taken up with W7) and my highest went to the RAM which got 9.3 so I wanted to know how far I am from the best performance. WEI is not definite but it is a good indicator.
WEI is not a good indicator at all...
It isn't even consistent with itself. Different runs can return drastically different scores. The best way to decide what you need is still to look at the hardware requirements for your software and make sure you meet or exceed them.