Less than two weeks after Nvidia released its last batch of graphics drivers, a new crop is ready to harvest. This latest 331.40 release carries a beta moniker, so it lacks the WHQL certification of the previous 327.32 drivers. The beta status is fitting, though; Nvidia says this release ensures "maximum performance and system stability" in the Battlefield 4 beta, which begins tomorrow.
The new drivers have a few other tricks up their sleeve, including support for a new ambient occlusion technique called HBAO+. This DirectX 11-based approach is supposed to offer better image quality than Nvidia's old HBAO mechanism while consuming fewer GPU resources. Nvidia says HBAO+ uses nine times the samples per pixel but takes only 2.4X longer to render per frame. Here's a nice-looking shot of the shadows it produces:
This page provides a larger look at the scene with a handy slider that lets you compare HBAO and HBAO+. The difference between the two looks pretty stark to me. HBAO+ is natively supported by Splinter Cell Blacklist. If the other games you play don't have explicit support for the feature, you can enable it via the Nvidia Control Panel.
Speaking of other games, Nvidia says the 331.40 drivers boost performance in "several PC games when compared to the GeForce 327.23 WHQL drivers." The release notes (PDF) aren't more specific, though they indicate that the latest drivers add or update the SLI profiles for 17 different titles.