I had crashes like this when have high amount of data flowing through my system bus.
I found out that it is caused by bugs in hard disk or netowork card drivers or by too many devices sharing the same IRQ. When device drivers dont handle parallel IRQ requests accordingly the system can crash.
When many devices share the same IRQ the chances are higher that you run into these conflict situations. Try to make sure you have the latest drivers and that you dont have too many devices with high troughput on the same IRQ channel.