Ok, now I have real server fault ;)

After some time from booting (about one minute) my server hangs. All I can do is hard reset. Then after restart in /var/log/kern.log I can find:

Jul 29 22:38:57 leonidas kernel: [   90.729598] longhaul: Failed to set requested frequency!
Jul 29 22:38:57 leonidas kernel: [   90.731252] longhaul: Enabling "Ignore Revision ID" option.
Jul 29 22:38:57 leonidas kernel: [   91.201461] longhaul: Failed to set requested  frequency!
Jul 29 22:38:57 leonidas kernel: [   91.201482] longhaul: Disabling ACPI C3 support.
Jul 29 22:38:57 leonidas kernel: [   91.204230] longhaul: Disabling "Ignore Revision ID" option.
Jul 29 22:38:58 leonidas kernel: [   91.416133] longhaul: Failed to set requested frequency!
Jul 29 22:38:58 leonidas kernel: [   91.416152] longhaul: Enabling "Ignore Revision ID" option.
Jul 29 22:38:58 leonidas kernel: [   91.960048] Clocksource tsc unstable (delta = -105611479 ns)

I found some resources on the net, and it said to change clocksource, or disable ACPI. I tried disabling ACPI but it didn't help (but I noticed there was longer time before hanging). I can't change clock to hpet, because my system doesn't have such one.

Output of cat /sys/devices/system/clocksource/clocksource0/available_clocksource:
acpi_pm jiffies tsc

My system is ubuntu server on VIA Epia hardware.