In 3.1 and earlier, the "Auto Dots"slider was in Preferences >Draw, and controlled the threshold at which models would be displayed as vertexes. In 3.5, it does not seem to be there, and I can no longer locate it anywhere. Has this functionality been moved, or taken out?
In the case of the latter, I would strongly encourage its return. While most people working at screen resolution with Zbrush as an intermediate part of a pipeline would probably seldom have need of it…
…people (like me) working for the purposes of Illustration (the alleged original purpose of this software), at print resolution can face crippling performance burdens trying to draw out and position very dense tools in documents of that extreme size.
Furthermore, consider that Zbrush’s quirk of disabling the behavior that previews the mesh at lower resolutions during navigation transformations when part of the mesh is hidden was fine in 2.x, when partially visible meshes meant you probably didnt have enough polys on screen to pose as much of a burden. But the Polycounts that Zbrush has developed the ability to accomodate mean you can very easily find yourself with a mesh that, counter intuitively, is much more difficult to manage with part of it hidden than with the whole thing visible, due to the loss of preview-res reduction while transforming. The Dots mode was the only way to address this when it became a burden.
Anyways, hopefully someone will point out where it has moved to, and my little mini rant here will have been for nothing. 
Thanks!