I’ve had a mixed experience using the Nvidia GTX 980 card in Navisworks and Revit, but I have one particular tip that helped in Navisworks 2017:
Turn OFF CPU Occlusion Culling

My CPU is an i7-6700K that I generally OC to 4ghz. But obviously there is some slowdown when both of the Occlusion Culling boxes are ticked.

Aside from the usual tips of using ‘Guarantee Frame Rate’, Automatic Clipping Planes, and playing around with the File Options – Frame Rate, I found that turning off CPU Occlusion Culling and leaving GPU Occlusion Culling on made a real difference for the better.

My main video card is a Nvidia Quadro FX 580.  However, I wanted to run more than two monitors.  So I borrowed a old GeForce 7300 LE and installed it into one of the other PCI-E slots on my Gigabyte EX58-UD4 motherboard.

This is NOT an SLI rig.  But I can run it in a ‘hybrid mode’ where I’m essentially getting access to 4 monitors.  I try to make sure that I always run my main Revit instance on the monitor that is plugged into the ‘good’ FX 580 video card.

The main lesson here is that you need to install GeForce drivers to make this all happen properly.  The Quadro drivers do not seem to work very well in this hybrid setup. 

I am running 275.33 drivers, which you can download from here:
GeForce 275.33 Driver

This GeForce driver also includes cool stuff like overclocking options in the Nvidia Control Panel.