This is the first WHQL release from the Release 280 family of drivers.
This driver package supports GeForce 6, 7, 8, 9, 100, 200, 300, 400, and 500-series desktop GPUs as well as ION desktop GPUs. This driver package also includes the 3D Vision Controller driver.
New in Release 280.26NVIDIA SLI
- Enables SLI technology on SLI-certified motherboards with AMD chipsets: 990FX, 990X, and 970.
MultiGPU issues fixed:
- [SLI], GeForce 500: Crysis 2 there is screen flickering when played in 2-way SLI-way SLI. 
There are many more fixes, please read the download description for that. We have a discussion thread open on these drivers right here.
For those interested, there is aso a beta developper driver available supporting OpenGL 4.3 under build 280.28 Beta, more info here.