Re: do Pentium4 & PentiumM consume about the same at their lowest possible freq?

[Len Brown <lenb@kernel.org>]

On Friday 03 August 2007 12:56, Roberto De Leo wrote:
> Hi all,
> I am not sure this is the right place where posing my question, if not 
> please suggest me a better one!
> 
> I come to the question.
> I happily used the speedstep kernel module with my centrino laptop and 
> it really made a difference in terms of battery duration (actually now I 
> have a celeron-m based laptop and the difference does not seem so 
> evident, but I still have little statistic on it).
> Now I need to replace my main home 'desktop' PC and I am tempted to buy 
> a PentiumM-based minit-itx MB (e.g. the AOpen i945GTt-VFA) in order to 
> decrease the power bill (my PC is on 24/7), but since mini-itx MBs are 
> quite expensive I'd prefer first to know the following: can the  "Intel 
> Pentium 4 clock modulation" kernel module (or maybe the "AMD 
> Opteron/Athlon64 PowerNow!" one) bring the corresponding CPUs to consume 
> as little as the "Intel Enhanced SpeedStep" does for a centrino? This 
> info is quite important but I could not find it anywhere!

In general, no -- you are better off with a mobile-optimized processor.

indeed, under many conditions, using pentium 4 clock modulation will
actually increase energy use, rather than decrease it.

-Len