From: Nebojsa Trpkovic <trxman@gmail.com>
To: cpufreq@lists.linux.org.uk
Subject: Re: Centrino: undervolting and further reducing heat
Date: Wed, 18 May 2005 14:45:38 +0200 [thread overview]
Message-ID: <428B38F2.5080907@gmail.com> (raw)
In-Reply-To: <d6f982$h87$1@sea.gmane.org>
I use undervolted AMD64 on two gentoo boxes for months:
1. socket 754 nforce3-250gb, athlon64 3000+ (Newcastle core) overclocked
to 2.4GHz and undervolted to run @1.45V
2. socket 939 nforce4 ultra, athlon64 3000+ (Winchester core)
undervolted to run @1V at 1GHz and @1.275V at 1.8GHz (stable voltages
suficient to run prime95 for hours were 0.9V at 1GHz and 1.175V at
1.8GHz but I like to be 110% safe so I've left extra 0.1V just in case)
Ofcorse, I had to manualy modify powernow-k8.c
;)
Daniel Bonniot wrote:
>
> Hi,
>
> I have a dothan 1.6 GHz processor, and i've been investigating how to
> reduce heat to minimize fan usage. One very promising avenue is
> undervolting. According to several online articles, there is a large
> potential for undervolting. I ended up modifying speedstep-centrino.c
> to test it out. Results are very positive: it can run under heavy load
> at 1.6Ghz with only 972mV (down from 1340mV). This decreased
> temperature by 10���C! At 600MHz, the minimum 700mV was sufficient.
>
> I understand that the driver needs to be conservative by default, but
> given the huge benefits, it would make a lot of sense to offer a way
> to specify lower voltages to those who want to. Has anybody
> investigated this possibility, or already started working on it? What
> would be a good interface to specify the voltages?
>
>
> Independently of this feature, I wonder how it's possible to further
> reduce consumption when the system is mostly ideal, and even 600MHz is
> more than needed. The idea being to let the system cool down even more
> in that case. Is there any existing way to achive this on linux? One
> possibility I found in the intel docs is the IA32_THERM_CONTROL MSR,
> which can reduce clock speed by 12.5% to 87.5%. Am I right in thinking
> that it could be combined with speedstep to achieve even lower power
> consumption states? Are there other possibilities?
>
> Cheers,
>
> Daniel
>
>
> _______________________________________________
> Cpufreq mailing list
> Cpufreq@lists.linux.org.uk
> http://lists.linux.org.uk/mailman/listinfo/cpufreq
>
next prev parent reply other threads:[~2005-05-18 12:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-18 11:36 Centrino: undervolting and further reducing heat Daniel Bonniot
2005-05-18 12:45 ` Nebojsa Trpkovic [this message]
2005-05-18 13:57 ` Aaron Spettl
2005-05-18 16:07 ` Wes Felter
2005-05-18 23:15 ` Daniel Bonniot
2005-05-25 13:00 ` Bruno Ducrot
2005-05-25 13:35 ` Daniel Bonniot
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