Essentially, they completely broke the rendering engine by hard-coding assumptions about where the camera would be into the driver. Move the camera slightly (such as in the developer version of 3D Mark), and everything is a garbled mess.
OK, I take the optimizations back, I didn't know what exactly they were doing.
What I was thinking about when I talked about a performance slider a few days ago was playing around with some glHint parameters, or the worst thing, giving the user the ability to force drawStridedFast instead of drawStridedSlow, but that would be close to what nvidia was doing here(if the story is true).