the latest drivers didnt do much for most people. some saw a performance increase, others had it in reverse, as the new drivers decreased the maximum clock their card could go at when overclocked. Not many tech sites did a revamp on the new drivers as it was more of a marketing move against amd rather than an actual major performance boost.
example of MoH warfighter(frostbite 2 engine game) with 12.11 vs 310.33
http://www.hardocp.com/images/articles/1352242694lIkKba3wQX_5_1.jpg
though what nvidia still has is sli vs crossfire fps stability in general through more titles
more or less sources im refering to
source 1
Source 2
Small example of what happened to people with the 310.33 drivers
Basically, the drivers benefitted people who used stock or slight overclocks, and hurt users who were benchers/heavy overclockers(the minority)