The big question is, when did you last run 3d mark? If you ran it a long time ago, then obviously you can't compare the before and after on the drivers.
Did you run 3D Mark, install the new drivers, then run 3D Mark again to see the difference?
If the last time you ran 3d mark was 5 months ago and you're score was better, than you have to see what apps and hardware you may have installed that could be hindering the performance. You have to compare apples to apples to see if the driver change is what is really causing the performance difference.