Nvidia Linux drivers never had the same stability and performance as the Nvidia drivers on Windows OS. Nouveau drivers are even less performant, and rely on reverse engineered code, and while they might seem to work in some cases, fail in other …
I have a GTX 960 and never had any issues with the Nvidia drivers, dual display works fine, but both displays are 60Hz, and both are connected via DVI. With Display Port maybe other models are affected by the latest drivers, but if you have the same issue with 470xx driver, then you can look into enabling early KMS.