To reproduce:
1. Create a new project
2. Add a new uGUI text
3. Duplicate it 10 or so times (the more the merrier)
4. Select all of the texts and then change all of their font sizes to something really big (i get the best results by sliding, increasing and decreasing the font size). Errors about the font size being to big pop up and unity eventually freezes (task manager shows lots of ram usage)