You can now download the official 326.01 WHQL Windows 8.1 Preview Driver which was released by NVIDIA moments ago. Since a few users have reported this driver did not show up in their Windows Update, NVIDIA is releasing them separately so that users may have access to them.
If you already installed these drivers and are not experiencing any issues, you do not need to reinstall these drivers below. If however you did not see this driver through Windows Update and had to install a modified version, we ask that you first attempt a clean install using the driver below. Many support cases we receive from end users are easily solved by performing a clean install.
Please post your feedback on this driver right here. This driver supports Windows Vista, 7, 8.