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PatrickMay16 07-10-2007 12:26 PM

CPU frequency scaling
 
BENIS DENIS! DENNACE DENNACE DENNACE.

Alright. Now let's get to business.
Do you use CPU frequency scaling in linux? I do, on my laptop and desktop computers.

In my desktop, I have an Athlon64 3800+, and I have enabled the 'cool'n'quiet' function. It didn't work at first, but it worked fine after I updated my bios to the most recent version available.

In my laptop, an Asus Z35FM with the Celeron M processor, I didn't know what to do to get it working. After asking for help amongst some people, I found that loading the 'p4_clockmod' module would enable it. It works very well now.

Do you use it? And laptop users, do you notice any increase in battery life when you use it?

Jorophose 07-10-2007 12:49 PM

Erm... What's CPU frequency scaling? *flees from various thrown objects*

slackhack 07-10-2007 12:57 PM

i use cpufreq on my laptop, works great.

i have an A64 3200+ -- how do you enable "cool'n'quiet"? is it a bios option only in certain motherboards, or a kernel + software capability?

nx5000 07-10-2007 01:10 PM

I use speedstep_centrino (Intel M) and enable powersaving (thanks to this amazing tool from Intel) for some devices that support it. With only X-Window loaded, I get +5h of autonomy at 600Mhz using governor ondemand. With several dozens of windows open, firefox, music, gkrellm it stays very often in lower speed. If I want quick response, I will set profile performance (applet klaptop in kde).

Before I was using http://cpufreqd.sourceforge.net/ but I haven't reinstalled it yet. With this, you can define complex profiles: when temperature goes too high, lower freq; when xine is running, set the higher freq,..)


It works quite well!

PatrickMay16 07-10-2007 01:20 PM

Quote:

Originally Posted by slackhack
i use cpufreq on my laptop, works great.

i have an A64 3200+ -- how do you enable "cool'n'quiet"? is it a bios option only in certain motherboards, or a kernel + software capability?

Check the power management area of your bios. There should be an option to enable or disable it... there is in mine. If it doesn't work even when the option is enabled, you might need to update your bios; that was the case for me.

I dunno much about the kernel stuff... but it is the 'powernow-k8' module which does the cool'n'quiet stuff, I think.

slackhack 07-10-2007 02:26 PM

Quote:

Originally Posted by PatrickMay16
Check the power management area of your bios. There should be an option to enable or disable it... there is in mine. If it doesn't work even when the option is enabled, you might need to update your bios; that was the case for me.

I dunno much about the kernel stuff... but it is the 'powernow-k8' module which does the cool'n'quiet stuff, I think.

excellent! i just installed powernow-k8 and it works. bios was set to auto, so i just assumed it didn't work in linux. thanks!

brianL 07-10-2007 02:29 PM

Real (Wo)Men dont need CPU frequency scaling...whatever that is.

charle97 07-10-2007 02:55 PM

i use cpu frequency scaling on my desktop to lower electricity usage.

Crito 07-10-2007 04:35 PM

To make full use of AMD's "Cool 'N' Quiet" you need a special four pin PWM (pulse width modulation) fan. The high-end retail processors come with them. My boxed 64-bit Sempron 3000+ didn't.

Anyway, the objective isn't to get the lowest temp possible, believe it or not. The objective is to get the smallest difference between min and max temps, thereby minimizing thermal "stress". So you might actually see higher idle temps when enabled. Heck, if you live in Norway the CPU fan might not even turn on! :o Don't be alarmed! It's supposed to work that way. ;)

PatrickMay16 07-10-2007 06:11 PM

Quote:

Originally Posted by slackhack
excellent! i just installed powernow-k8 and it works. bios was set to auto, so i just assumed it didn't work in linux. thanks!

YES! Congratulations, man. And here's to a world of coolar processors.

SlowCoder 07-10-2007 08:07 PM

Quote:

Originally Posted by Jorophose
Erm... What's CPU frequency scaling? *flees from various thrown objects*

Frequency Scaling is the act of changing the operating speed of your processor, which in turn saves electricity and reduces heat, allowing fans to run slower. Sort of like overclocking, but reverse, with the intent on increasing the overall lifespan of your system.


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