Can't get 120hz using Sony Bravia XBR-55X850D as a monitor

[JCuomo85]

Just purchased a Sony XBR-55X850D. 55" 4k 120hz. My nVidia (GTX 970) Control Panel shows it as the TV model, but Windows (10) Device Manager shows it as Generic PnP Monitor. Neither allow me to change from 60 to 120hz. My video card drivers are up to date. I bought a new HDMI cable thinking it was that, but it hasn't helped. I have the resolution set correctly (3840x2160? Something like that, I'm in bed now). Any ideas?

 

[bignastyid]

There are no displays that support 4k@120Hz input signal. Your TV repeats frames to mimic a 120Hz signal but will only accept a 60Hz input. This is the norm for TVs.