NVIDIA has released WHQL-certified GeForce drivers today for Windows 8.1
You can install the new GeForce driver version 326.01 for Windows 8.1 from Windows Update after you install the Release Preview.NVIDIA Drivers for Windows 8.1 Release Preview Now Available
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.