Here is a listing of the new image quality enhancements in G80 based hardware.
Nvidia showcased a lot of cool things at Editor's Day this year. Beyond the new DX10 graphics cards, they showed us some tools and features that will be enabled on G80 based cards. The first of these is an image quality functionality they have patented called Coverage Sampled Antialiasing (CSAA).
This new version of antialiasing uses a Boolean coverage at 16 sub-samples. According to Nvidia it can compress "redundant color and depth/stencil information into the memory footprint and bandwidth of four or eight multisamples." This new quality level works more efficiently by lessening the storage cost per sample. If a CSAA selection cannot work within a particular application (game), then the driver will revert back to a traditional AA method.
Here is a listing of the coverage sample cost reductions (click for a larger image).
Here is an example of the image quality improvement of 16xQ CSAA over traditional 4xAA. The footprint is a little more than 4xMSAA but produces a better result.