If you have a recent NVIDIA GTX10XX or RTX20XX card then driver 417.71 will allow it to work with the much cheaper AMD Freesync monitors and do Adaptive Sync.
DisplayPort only for now I think.
https://nvidia.custhelp.com/app/answers/detail/a_id/4764
https://nvidia.custhelp.com/app/answers/detail/a_id/4765
https://nvidia.custhelp.com/app/answers/detail/a_id/4766
https://nvidia.custhelp.com/app/answers/detail/a_id/4767
https://nvidia.custhelp.com/app/answers/detail/a_id/4768
https://www.pcworld.com/article/3333637/components-graphics/nvidia-driver-freesync-monitor-support-geforce-graphics-cards.html
It’s the start of a new era. On Tuesday, Nvidia fulfilled its CES promises by releasing GeForce driver 417.71, which lets GeForce graphics cards tap into the Adaptive Sync capabilities of AMD FreeSync monitors for buttery-smooth, tearing-free gaming. Previously, GeForce GPUs could only synchronize their refresh rates with Nvidia’s own G-Sync displays, which tend to cost much more than FreeSync displays. You can snag the driver in the GeForce Experience app or on the GeForce website.