What is "shimmering?"

[BoltAction]

First off, hello nV News Forums users. :)

Now for the question:
What do you guys mean by "shimmering?" Can someone provide a screenshot of what this is? Thanks a lot.

[Ruined]

http://www.nvnews.net/vbulletin/showthread.php?t=38888

Was fixed for most people here with the Negative LOD Bias clamp in the 67.02 drivers.