viper_racing_54

It is a different issue but you could try it anyway...seems like someone had success enabling SLI using 320.49 Y500 SLI doesn't work after Windows 8.1 preview - Lenovo Community

I tried with these 320.49 drivers. They installed successfully, and Nvidia control panel had SLI enabled, but CPU-Z reported that only one GPU was working. The frame rates is also the same without SLI enabled.

There is a horrible bug with windows 8.1 RTM/final and the 650m/750m sli configs.

No driver even the latest 331.40 driver

seems to fix this bug

I have this exact same issue on Y510p SLI on 8.1 x64. I thought the beta drivers would fix it. At the moment, the second GPU is doing nothing...

Not sure how to flash the GPU, and not really sure how this would help.

Any suggestions?