I have used 1 GTX 970 for the last year and it has worked great, but this year I upgraded my whole build with a new cpu, mobo, ect and I added a second GTX 970, they both show up in device manager, Nvidia control panel, and geforce experience but The option to configure SLI does not show up in Nvidia control panel, I am sure a have two of the exact same models. I have tried switching their positions, putting the SLI bridge on the other side, and reinstalling my drivers.