On Fri, Jul 29, 2005 at 09:04:36AM +0100, Neil Marjoram wrote: > Can anyone help? I have had my system lockup twice now in the last week, > I am most shocked! Both occasions the system has blown out my X session, > and then locked completly forcing me to hard reset the system. I cannot > reproduce the error, the only apps I was using are Thunderbird, Firefox > and terminal I am using KDE. Linux tux 2.6.12-1.1398_FC4smp #1 SMP Fri > Jul 15 01:05:24 EDT 2005 x86_64 x86_64 x86_64 GNU/Linux > The system is a Tyan twin AMD opteron 64 system (2.6Ghz) with 2 GB ram. > The system is upto date with patches. > > <ffffffff801165c7>{do_machine_check+871} Your CPU raised a machine check exception. These are triggered most of the time due to hardware problems (overheating, overclocking etc), but can occasionally be triggered by bad drivers doing bad things like reading from non-existant areas of memory. What drivers do you have in use ? Coincidentally, the last week or so I've heard of countless problems with Tyan boards in certain configurations. Boards that seem to work just fine with smaller amounts of RAM start misbehaving when bigger DIMMs are added for eg. You may want to see if there's a BIOS update available. Dave