On Thu, 27 May 2010, dave b wrote:

> That was just a simple test case with dd. That test case might be
> invalid - but it is trying to trigger out of memory - doing this any
> other way still causes the problem. I note that playing with some bios
> settings I was actually able to trigger what appeared to be graphics
> corruption issues when I launched kde applications ... nothing shows
> up in dmesg so this might just be a conflict between xorg and the
> kernel with those bios settings...
> 
> Anyway, This is no longer a 'problem' for me since I disabled
> overcommit and altered the values for dirty_ratio and
> dirty_background_ratio - and I cannot trigger it.
> 

Disabling overcommit should always do it, but I'd be interested to know if 
restoring dirty_ratio to 40 would help your usecase.