I can rarely remember the steps (I prefer to open admin powershell, then "winsat formal", and then "Get-WmiObject Win32_WinSAT")
Something I noticed according to this Win32_WinSAT class entry:
"After Windows 8.1, WinSAT no longer assess the three-dimensional graphics (gaming) capabilities of the computer and the graphics driver's ability to render objects and execute shaders using this assessment. For compatibility, WinSAT report sentinel values for the metrics and scores, however these are not calculated in real time."
Indeed, on a decent older-desktop with a Radeon 4670, it returns a 9.9 for D3D:
CPUScore : 5.3
D3DScore : 9.9
DiskScore : 5.9
GraphicsScore : 6.2
MemoryScore : 5.4
TimeTaken : MostRecentAssessment
WinSATAssessmentState : 1
WinSPRLevel : 5.3
Just another tidbit/gotcha to be aware of.