Hi Cuboctahedron, yes the annotations are intended for pretty lightweight markup duty currently, like having 30 or so of them to make a light shop drawing PDF. It won't work well currently to have so many of them in a single model like you've got there especially with model units type scaling behavior.

Currently text with model units scaling is drawn with a pretty dense triangle mesh and when you have a lot of them it's too heavy and performance suffers.

I have several ideas on how to improve this when the text is small on screen, if you can please send me the .3dm model file of your heavy model with poor annotation text performance that would help when I'm testing it out for improvements in v5. Please send a file sharing link to me at moi@moi3d.com , thanks!

- Michael