[CentOS] Clock Drifts Off

[chrism at imntv.com]

Jim Perrin wrote:
> On 2/2/07, Matt <lm7812 at gmail.com> wrote:
>> I installed CentOS 4.4 32 bit on a dual core AMD64 motherboad.  Its a
>> Tyan Tomcat K8E motherboard with socket 939.  The clock keeps drifting
>> off like 5+ minutes an hour.  Run ntpupdate hourly to compensate.
>>
>> Any ideas why or how to fix?
>
> Probably a buggy/unsupported apci setup. Look for a bios update, or
> use the kernel options 'clock=pmtmr' or 'clock=pit'

Yup, I've had similar problems with some Tyan Opteron systems (even with 
current bios).  In /boot/grub/grub.conf add a kernel parameter like so:

title CentOS (2.6.9-42.0.8.EL)
        root (hd0,0)
        kernel /vmlinuz-2.6.9-42.0.8.EL ro root=LABEL=/ clock=pmtmr
        initrd /initrd-2.6.9-42.0.8.EL.img

Cheers,