We reached NVIDIA tonight for an official statement concerning this worrysome issue, and they quickly replied within less than an hour. NVIDIA's response is:
We are aware that some customers have reported fan speed issues with the latest 196.75 WHQL drivers on NVIDIA.com. Until we can verify and root cause this issue, we recommend that customers stay with, or return to 196.21 WHQL drivers. Release 196.75 drivers have been temporarily removed from our Web site in the meantime.
One of these gamers reported insane egg-cooking temperatures as high as 104'C. Among the complaints found in the Starcraft II Beta forums are the following: