Woohoo! Old thread I know but that last step worked for me! In all my years I thought antialiasing in Altium 3D was some sort of April fool's joke or the slider was for 2D - had never seen it work until just now. Turning off Ordered Blending and turning antialiasing DOWN to something like 4 or 5 did the trick. Also attempting to force to maxes in Nvidia control panel (seems to act more like a hint that the user "might appreciate some antialiasing at some point if you wouldn't mind terribly please"), GT 730 and older Altium. I assume this would be different for 18+.
I thought worth the post to say it can be done, and isn't a myth.