It seems that NX 8.5 doesn't use the Anti Aliasing functions that my Nvidia Quadro P4000 offers. See screenshots below. Even after going into the Nvidia control panel and doing an "override" on the 3D settings of NX (setting Antialiasing to max) it shows now improvement in line quality.
However, going into the NX settings (Preferences > Visualisation > Visual) and turning off "Line Antialiasing" as well as "Full Scene Antialiasing" results in an even uglier line quality.
How can I improve line quality further?