Having your old HDD installed will limit it to 5.9 even if you use your SSD most. WEI is a worthless metric
Right, I understand that.
As I had written in the post above, there is not HDD installed. There is only one (1) SSD installed, with a fresh copy of Windows 7.
Regardless of the useful/less-ness of WEI, I was asking why it shows as 5.9 as opposed to the actual score (7.7/7.8).
Anyway, I figured out the solution:
Download and install: Intel Rapid Storage Technology (RST) driver, from the intel website.
Install, restart, re-run WEI, voila! 7.7 for Primary Hard Disk.