Availability of XO-1.5 ATest-2 machines

John Watlington wad at laptop.org
Mon Jul 20 10:28:14 EDT 2009


On Jul 20, 2009, at 12:37 AM, Richard A. Smith wrote:

> Carlos Nazareno wrote:
>
>> Also, what determines the dynamic clock rate from 400MHz to 1GHz? Is
>> this auto-scaling on demand like with the old AMD Athlon64's? Does  
>> the
>> software automatically reduce speed to 400MHz when the unit is
>> unplugged?
>
> Dyanamic clock scaling is usefully for thermal limits only.  Scaling
> back the clock to 400Mhz will cost you power not save it.  Power  
> savings
>   are achieved by running as fast as you possibly can and then  
> entering
> one of the lower power states where the clock is stopped.

Which is why the C7-M takes this farther, and enters C4 automatically,
where the external clock generator is told to stop driving the chip  
and the
processor core power is dropped to an absolute minimum.

Cheers,
wad



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