NVIDIA announced it has issued a WHQL-certified GeForce driver for the release preview of Windows 8.1. On the company's blog, NVIDIA writes you can install the GeForce 326.01 driver for Windows 8.1 from Windows Update after you install the Release Preview.
A direct link was not provided.
NVIDIA has long been committed to working with Microsoft to ensure the best possible Windows experience for GeForce users. Our close working relationship with Microsoft allows us to provide WHQL-certified GeForce drivers via Windows Update on Day 1 for key milestones such as this Release Preview.
It’s a substantial effort that requires hundreds of man years of engineering time and thousands of hours of testing and certification, but it’s essential to ensure optimal performance and stability for the world’s largest gaming and productivity platform.