It is blank because when using Rivatuner, you use much greater LOD than available through the driver.
When using the driver at "for performance" that is around -1 or -2 in the LOD in Rivatuner.
For 3dmark, that is way to much detail.
In other words:

Stay away from the driver details if you are using the Rivatuner and the LOD tweak within it.

Mac