I don't why, but the game is running much better since...i don't have a clue. The game is still crashing from time to time during startup when a character is loaded. But once it is loaded, i can play for hours most of the time.

The only thing i have noticed is, that when my NAS is wakened (there are various reasons why) during play, the game is likely to crash. In addition the game is much more sensible to parallel network traffic than before. I have a 50 Mbit connection at home and until now my wife could stream a tv show in parallel via ATV and the game didn't give a damn about it. Now the traffic of "death" is around 50%, more is too much for the game.

I'm using the HC client right now, running OSX Yosemite Beta 5.