How to diagnose system freezes?

[Wojciech Puchar]

> One of my 9.1-BETA1 systems periodically freezes. If sound was playing, it 
> would usually cycle with a very short period.

so interrupts are off.

> And system stops being 
> sensitive to keyboard/mouse. Also ping of this system doesn't get a response.
> I would normally think that this is the faulty memory. But memory was 
> recently replaced and tested with memtest+ for hours both before and after 
> freezes and it passes all tests.

this is not a proof but if you can compile generic with make -j50 it is 
quite a good proof memory is not..

> One out of the ordinary thing that is running on this system is nvidia 
> driver.
this is the most probable reason.