What I do is make a selection and hit NUMPAD ‘.’ to center it in the view. This has a way of resetting scale factors for zooming. I have to do this in other packages as well, due to the same issue. Remember that if you have one point selected, it will only center, but with 2 or more points it will center and zoom all the way in to the extents of the to points, since it has a reference to work with. I hope this fixes what you are dealing with, because it sounds like you’re running into zoom limits, and this will reset them.
OK, thank you, ajm…I’m going to have to remember this.
I did notice that the problem went away if I went to Ortho. Perspective was just brutal, but ortho seemed to be free of whatever was slowing Perspective down.