"Expreview is drawing some wild conclusion that its related to Nvidia’s impeding launch of Fermi based cards and as such they want to prevent the cards from being overclocked. This seems like a little bit of a long shot, especially as the drivers are WHQL certified for use with the current crop of cards. Hopefully Nvidia will sort out this issue as we can imagine that quite a few people will be miffed about it, least not the competitive overlocking crowd."
http://www.semiaccurate.com/2010/01/21/latest-nvidia-drivers-kill-overclocking/
http://www.semiaccurate.com/2010/01/21/latest-nvidia-drivers-kill-overclocking/