Here is what I wrote to AMD support re: a low Aero rating.
"I am only getting a 3.7 rating for the "Desktop performance for Windows Aero" whereas the rating for "Gaming Graphics" is 5.8. Why such a difference? Shouldn't I be getting a higher Aero rating? Am I missing a setting somewhere? All of the other ratings (CPU, HDD, RAM) are 5.0 or better."
Their reply was the following.
"Normally, a rating for "Gaming Graphics" of 5.8 indicates a correct assessment. However, we have noticed that the Windows Aero rating may appear lower even though the actual performance is unaffected. We have documented the issue and have investigated preliminary results with Microsoft for similarly low ratings. In the interim, please confirm that the latest Catalyst 9.x is installed. In addition, install the latest motherboard (Northbridge) chipset drivers for MS Windows 7.
NOTE: These drivers are required and will affect the way that the motherboard communicates with the graphics card.
If you continue to experience the low rating for Windows Aero, we encourage you to report your observations to AMD Software Engineering through the Catalyst Crew Feedback Form.
Please encourage others who have experienced the issue to do so as well."