[time-nuts] PC Clock adjustments

[Bruce Griffiths]

David Ackrill wrote:
> David Ackrill wrote:
>   
>> Bruce Griffiths wrote:
>>
>>     
>>> Automatic adjustment of the clock rate to minimise power is incompatible 
>>> with accurate timekeeping.
>>>
>>>       
>> Thanks for the responce Bruce,
>>
>> I don't think the newer PC has that facility, and the load on it is not 
>> all that great normally.  
>>     
>
> AH!  It does have a utility calld "Cool n' Quiet, and it seems that can 
> only be dissabled in the BIOS, from what I have read.
>
> I also have installed the RightMark CPU Clock Utility, to try and get a 
> grip on what is going on.
>
> Throttling seems to be enabled, the difference between the Core Clock 
> and the 'Throttle' seems not that great.
>
> Also, the older machine (running Windows 2000 pro) also seems to have 
> Cool n' Quiet on it, so I'm wondering if this is having such a great 
> effect on the XP machine?
>
> Anyway, at least I know more about the motherboards and operating 
> systems in both my PCs now.  :-)
>
> Dave (G0DJA)
>   
Dave

If only the application/utility made use of the so called high precision 
timer available in all recent motherboard chipsets.
This timer doesnt have the resolution achievable by counting cpu cycles, 
however at least its clock frequency is constant.

See:
http://en.wikipedia.org/wiki/SpeedStep

Where it explains why Windows2000 may not throttle the cpu back whereas 
XP is more likely to do so.
Disabling XP's use of Speedstep is a slightly trickier:

http://www.bay-wolf.com/speedstep.htm

Bruce