Why does QGIS 2.16 have longer load times than 2.8, especially working with tables?

I was previously running an LTR version of QGIS (2.8.9 I think). I installed 2.16 and found that opening tables takes a very long time. Deleting columns in tables now takes hours as opposed to seconds. It also seems to load and delete columns one by one instead of all at once. I tried the 2.14 LTR and am experiencing the same problem.