[zoson]

Your stress testing is lacking. That is why your computer is crashing. The nature of processors are that within the chip there will be different hot spots depending on what the chip is doing.
Because not all transistors are created equal, the rest of the chip may run at 2400+mhz but once that one logic unit is accessed and gets hot, if it cannot sustain the logic, your computer will crash.
I imagine you must be completely deaf with that kind of Fanage. I used to have a rig that was somewhat similar to that... I refused to admit it, but I was deafinately deafened by the noise it created.
Water cooling is a far better choice, especially since you have a large case. Not only does water cooling deal with hot spots much more effectively, it will keep your over all temperatures lower as well, and allow for even more overclocking.
Your luck is incredible though... I haven't seen the likes of an amd chip that overclocked >1GHz in awhile.
-Zoson