i have the new samsung monitor with 49 inch and 144hz. unfortunately i can't do anything with 40-60hz=) but thanks for the feedback. i will contact nvidea directly. =)

I use the display port on my card to connect to the 4K Samsung U28E59D monitor. The cable is marked
BN39-01879D 1623 GM. - Unfortunately, I don't see which version is used for communication. I assume that the necessary version is embedded in the driver update from NVIDIA.
But maybe it helps that the latest big games (e.g. Witcher3, WW3) run without problems at 40-60Hz under full-screen 4K display.