Already two times the game constantly crashed at a certain point.

1. low level Barb when I found the enchanter and tried to enchant an item

2. Engineer at final room in ACT1 (Grand Regent Eldrayn)
I saved the game before the final room. Few moments after engaging the boss the game always crashed

(I didn't have any issues at other locations/situations)

Turning on V-sync solved the problem and I could continue