Just checked Nvidias site the new driver is out the Version is : 81.85
the benefits as said by manufacture:
Example: You can use a GeForce 7800 GTX from manufacturer ABC with a GeForce 7800 GTX from manufacturer XYZ.
Note: You must still use two graphics cards that have the same GPU. For example, a GeForce 7800 GT must be matched with another GeForce 7800 GT (not with a GeForce 7800 GTX or a GeForce 6800 Ultra).
Mix and Match Graphics Cards with Different Input/Output Ports
Example: You can use a GeForce 6800 GT with Dual DVI & TV-out with a GeForce 6800 GT with Dual DVI & VIVO.
Mix and Match Graphics Cards with Different Clock Speeds
Example: You can use a higher clocked GeForce 6600 GT 550/525 with a standard clock GeForce 6600 GT 500/500.
Mix and Match Graphics Cards with Different Memory Sizes
Example: Using Coolbits, you can use a 128MB GeForce 6800 GT with a 256MB GeForce 6800 GT.
Note: NVIDIA recommends that SLI customers, whenever possible, purchase graphics cards with matching memory sizes. When dissimilar memory sizes are enabled to work together using Coolbits (value set to 18), the effective memory size for each card becomes the smaller of the two memory sizes.