I decided to try printing a simple overhang test model and it was disastrous. The overhangs started curling so badly that the print head started hitting the model with a clicking sound. Eventually it got bad enough that the print head shattered the arm off the print.
This was with the aux fan on it’s default 70%:
It seemed worse for the sides closest to the aux fan, so I ran it again with the aux fan turned off, but it didn’t make any difference, still started hitting around 40 and snapped the front arm off again:
