I tend to freeze a lot while playing my adept.
I realized that when I switched to my warrior to level him up, that I managed to go 3 levels 15-18 without a single freeze or lag out. Also I still have not had any problems with my warrior.
This is just a theory but, could it be that my adept is freezing all the time because of spells and some memory problem?
I usually freeze when casting the return home spell, astrum magnus, or when another adept goes by my screen.
I was hunting with Happy Ending at trolls and it would seem like everytime he went by my screen and did a spell, my screen would freeze and lock up my computer for several minutes, even in windowed mode. Sometimes when I would log back in, my character would almost automatically die from putting me back at trolls or would just spawn me at the square. Most of the time I have gotten lucky and been spawned at the square when logging back in.
I also started a new adept character and was hunting with some other new characters, but we all kept lagging out. The other 2 characters were adepts aswell. We could run around on the same screen and be fine but, when it came to fighting and spell casting we didn't have much luck, and were all having problems.