On Sun, Jan 23, 2011 at 00:14, compdoc <compdoc at hotrodpc.com> wrote: >>I have built a new PC on which I've installed CentOS 5.5 64-bit (with >>updates) which after some hours of running suddenly either hard freeze >>or instant power off. > > > Can you check a setting in the bios - see if there's an option named: PCI > Latency Timer No, only some frequency adjustment of the PCI-Express bus. Update: After some more days of running Fedora 14 those disk timeouts has started to appear. After a search on the net about similar NCQ problems I added this to /etc/rc.local yesterday, and so far I haven't seen any disk timeouts since then: for D in sd{b,c,d,e,f,g} ; do echo 1 > /sys/block/$D/device/queue_depth done Eventually I wish to install CentOS 6 and hopefully I will not have the same problem as with CentOS 5.5. In the mean time I will make a try with Scientific Linux 6 alpha or RHEL 6 beta2 and see what happens.