If your Windows 7 computer computer has a processor that has more than 16 megabytes (MB) of L3 cache, and when you run WEI or WinSAT, the test fails with following errors respectively:
Could not measure system memory performance
The buffer size is too large. Max is 32 MB
In this case you can apply hotfix from KB2619497 and see if it helps you.
If you encounter an error or are unable to update your WEI score. Or maybe a figure is shown, but next to it, is mentioned in faded letters Windows Experience Index : Unrated, see this.