With Nvidia's previous drivers, AMD cards had a notable advantage over Nvidia's GPUs, especially with TressFX enabled in the new Tomb Raider that was just released. The new 314.21 beta driver aims to close this gap a bit.
Beyond the performance gap closing, the new driver also aims to increase Tomb Raider's stability and remove potential artifacts on normally functioning cards.
Lastly, the new drivers also add a number of new SLI and 3D Vision profiles.
The 314.21 beta driver is available for download here (opens in new tab).