First and foremost. Its not DB thats "bad" in anyway. Its your computer that causes the crashes. Dont wanna flame someone, but since ive started to develop for DB ive seen alot of people who said that "db crashes every five min". Its usually people who dont take care of their computer and got alot of shit on it. Something Devious discovered was that alot of these crashes are due to either RAM running bad, overclocked "something" on the computer or just bad cpu.
Anyway, if you do get loads of crashes, try to get the lastest BIOs. Default all your clocks if you ever tried to overclock or something. Try DB on another computer.
Dont think that just because Diablo 3 can run on your computer. It can handle to run DB aswell as Diablo 3.
Blizzard is known for making CPU heavy games, so that you can play with any graphicscard.
What DB do is that for every frame in Diablo 3, it pauses that frame and make adjustments to the memory(RAM) of Diablo.
Some pretty heavy computing from DB needs to be done, so if you got a CPU thats running near 100% in Diablo 3.
There isnt so much left to do the heavy computing by DB.
Some of you might think that DB is "lightweight" but the calculations that it do is pretty complex and sometimes DB have to do alot of them.