Pls share your experiences from CPU freq. scaling

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

Hi,

I saw that kernel 2.6.* has the modules for scaling the frequency of the CPU. I also found a couple of programs on the portage for this task. Some of them are sophisticated some others are not.

I am thinking of buying a laptop (any good recommendation?) and I would like to know if this feature does actually reduces the CPU Temp and increases the time the laptop can run on a battery.

I would like to add that I tried the above feature (I used the program speedfreq for that) on my desktop and although I saw a change in the freq. of the CPU, that change did not change the CPU Temp. or CPU Voltage. Any idea why?

Thank you

Gherald

nenn · Posted: Mon Jan 24, 2005 12:39 am Post subject:

well im using a thinkpad r51 i can get everything working with a little elbow grease but freq scaling works fine with the right scripts, i dont use any programs other than some scripts i wrote, take a look

eric_42 · Posted: Mon Jan 24, 2005 1:27 am Post subject:

Get a toshiba! Mine works flawlessly with gentoo. The CPU frequency scaling isn't super advanced, but works fine. (Processor scales back 50% when battery goes to 50%.) Also, the battery monitor works perfectly, and the scroll buttons work without issue. IBMs are good too.

I am using an old 450 mhz P3 satellite. It might sound a little slow for gentoo, but I've got both a 2.3 ghz and a 1.4 ghz athlon compiling code for it across my network.

If you're dead set on buying a new laptop, I'd strongly consider getting an i-book. They're generally the same price as PC laptops, albeit with slightly slower processors. (really, it's worth it. The video and audio output is superb and OSX keeps getting better.) Also, i-books generally have long, long battery life, even at the lower-end. If you're convinced you want an x86 laptop, try to get one with an nvidia video adapter.

-eric

Gherald · Posted: Mon Jan 24, 2005 1:31 am Post subject:

The Toshiba porteges have the aboslute best name for a gentoo laptop

Haven't researched how good they are at running linux, but they look pretty cool otherwise.

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

Well, I was thinking of a Toshiba Satelite A75, it has a P4-M at 3Ghz with HT and it costs about $1500. But it comes with Ati 9000 with 64MB, and I would like it to have an Ati 9600 with 128MB.
The truth is that it is a little difficult to built your own laptop. Each company uses different combination of CPU, video card and monitor and they drive my crazy. I can not even compare the prices.

Anyway, back to the title of my topic.
Intel had this new processor, Centrino, which they claim that does not consume a lot of energy. On the other hand, it is slightly slower than P4-M and it is more expensive than P4-M.
So, I was thinking that if this CPU freq. scaling actually works, regarding the energy consumption, then I can buy a laptop with a P4-M.
This is why I asked you for your experience regarding the freq. scaling. I know that it works, but did it actually reduce the energy consumption?

Regarding the i-book, I know that Apple makes some really good machines, but firstly they are more expensive than the corresponding PC's and secondly I do not feel like spending all this time to learn a new OS or to install Linux on it.

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

IBM X40, has Centrino at 1.4GHz a 12.1'' monitor, 256MB memory, a 40GB HDD and it costs $2249.00
Well, but this is expensive.

Gherald · Posted: Mon Jan 24, 2005 4:05 am Post subject:

Well, I have the 1.2ghz version that came with 512mb ram, 8-cell battery, and 40gb drive which I bought last summer for $1800. Try http://www.pcconnection.com

First thing I did was add 1gb of more ram to it

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

I found that a laptop with a P4-M will run for 2.6hrs on a battery.
If you scale the CPU freq. down by a half, will the running time increase to 4hrs?

Kow · Apprentice Joined: 28 Dec 2003 Posts: 227

What CPU/certain setups support frequency scaling?

I have a MSI Master2-FAR w/ Dual Opteron 1.6ghz ....
_________________
-Kow

Gherald · Posted: Mon Jan 24, 2005 5:32 am Post subject:

Was this laptop doing automatic power management during those 2.6 hours?

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

Gherald · Posted: Mon Jan 24, 2005 5:29 pm Post subject:

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

It seems to me that nobody has checked the effect of CPU freq. scaling on power consumption.

kevin_s · n00b Joined: 24 Jan 2005 Posts: 5

Hello !

I'm using a Dell Latitude D600 machine for more than a year. I'm using Linux on it for about 6 months now. (Currently Debian, but i want to change, that's why i'm here

)

So, some of my experiences:

- Battery time
At the moment the winner of the "battery time" contest is absolutely the Intel Centrino (or the newer Sonoma) platform. If you want more battery time, buy a notebook with it. Yes, it has more battery time, than apple notebooks. Thats it.

- Kernel
Compile a 2.6.9 (or newer) kernel. From this release the kernel has a built-in "ondemand" cpufreq governor. Use that. This is the best way under linux to consume power.

- Processors
Most modern CPU's support somehow CPU freq scaling. Intel P4-M and P-M family processors and all AMD Athlon and newer support some kind of dynamic frequency scaling.

- XP and power management
Sadly, M$ XP has the most advanced power management features. So when you say "XP does not have the capability" you are wrong. Each and every manufacturer do their drivers for XP, so guess witch os has the best support for mobile environment...

Using linux on a notebook is not an easy task, if you want to get the maximum performance / battery time from your hw. I tweak my system since i installed linux on it, but i'm still not satisfied. If you want a quick and easy solution maybe use Suse linux. It has some great preconfigured laptop settings out-of-the-box.

bye,
kevin

kevin_s · n00b Joined: 24 Jan 2005 Posts: 5

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

kevin_s,

Thank you very much for your feedback.
I did not know about XP's ability to control the power consumption. I found windows so "stupid" that I am surprised to hear that they can do this.
I am also surprised, in a nice way, to read that with PM you increase the running time by 4. Centrino is not bad, but only if you buy a >1.7GHz one.

Thank you all for your feedback

servo888 · Apprentice Joined: 22 Feb 2004 Posts: 293

Ok YES; I have a compaq r3190 with an AMD64 3400+ (~2.5hrs battery life), and running at a lower speed such as 800Mhz will give you the best life - why? Because at 800Mhz the cpu is eating up about 35watts, while at 2200Mhz the cpu is eating up about 80 watts.

I like to lock my cpu at 800Mhz while it's on battery - simply because I don't need all the cpu power while I'm on the go. Plus I can get through class just fine.
_________________
www.garberdesign.com
"You need a Windows PC to listen to this music." -listen.com

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

kevin_s · n00b Joined: 24 Jan 2005 Posts: 5

Gherald · Posted: Tue Jan 25, 2005 10:16 am Post subject:

The 1.2 ghz ULV pentium-m in my X40 is fine, too.

A lot of people tend to get large, heavy laptops with faster processors than they really have a use for.

I chose a long battery life and low weight over everything else. And boy did I make the right decision.

Some other cool features of the X40:
- gigabit ethernet
- an atheros-based wireless that works without any hassles (uses madwifi-driver).
- the same legendary IBM keyboard quality as any other thinkpad -- on an even smaller form factor. I am still amazed at how they managed to fit such an awesome keyboard on such a thin and lightweight machine. They really do blow away their competition when it comes to keyboards... not even a powerbook comes close.

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

Right now I have a P4 at 2.4 (is 2 years old) and I am really happy with it. The only thing that I would change is the video card. I have a Radeon 7500.
So, I believe that a great computer will be a Centrino at 1.7/1.8 GHz with a Radeon 9700 with 128MB memory. This notebook will be powerfull, even for some coding, and will run for a long time on a battery, about 4hrs.

Maybe I am wrong but I compared a couple IBM notebooks and I found that they are a little expensive. A friend of mine told me about the VAIO-Sony notebooks, which are also a little expensive

kevin_s · n00b Joined: 24 Jan 2005 Posts: 5

MasterX:

If you want a good Centrino based notebook, take a look at these:
- IBM Thinkpad t42, t43 (expensive) r51 (quite cheap)
- Dell Latitude D600, D800
- ACER TravelMate 800, 8000 series
- ASUS L & M series
- Fujitsu Siemens Lifebook series
- HP/Compaq nc6000, nc8000 series

The most expensive in the list is the IBM T43, the D600 has (maybe) the best price/performance rating, and i think ASUS is the cheapest. (At least in europe, i dunno where you live) There are some other factor witch you didn't mention, and quite important when you buy a new laptop, like the weight, the size, the quality of the input devices, the quality of the LCD etc. So buying a laptop isn't an easy task

But maybe i can help, if you can tell me what do you want to do with your laptop.

bye,
kevin

MasterX · Veteran Joined: 26 Jun 2003 Posts: 1165

Kevin,

I did not check the notebooks that Asus, Fujitsu or Acer has, I will do it now, but I have checked the notebooks of Toshiba (Satelite) and Gateway.
What do you mean about the quality of the input devices? Besides the wireless card, which I make sure that it is 802.11g all the other are the same. Are not they? I am not talking about the monitor, this is another story, and I was told that a 15.4'' wide screen with 1440x900 resolution will be good.

Now, I will mainly use the laptop for word processing. Since I will install Gentoo on it, I want it to be quite powerfull. I might do some coding, but if it gets intense I might end up with a desktop. I will certainly want a laptop that I can play games on it. This is why I suggested a Centrino at 1.8GHz with a Radeon 9700 with 128MB. Moreover, my girlfriend has a P4M at 3.02GHz with HT. So I do not want to buy the most powerfull laptop nor I want to buy the least powerfull laptop. I am looking for a laptop that I will be able to use it for the next 3 or more and which comes with all these nice features (s-video, wireless card, network card, modem, 2.0 USB, etc)

kevin_s · n00b Joined: 24 Jan 2005 Posts: 5

MasterX:

I haven't got real experience with Toshiba notebooks, because they are irreally expensive here. (Hungary). Gateway may be an alternative.

The input devices are the keyboard and the touchpad. Before buy a new laptop you should try it.

about lcd's:
If you want a portable note (<3kg) the 15,4" isn't a good choice. But if you doesn't concern about the weight, 15,4" may be a good choice.

So, for word processing any kind of centrino is a good choice. For coding buy more memory

Once, when i had to develop some stuff, and i'm running winxp, Visual studio for development, and a VMWare with a windows server 2003 running an MS-SQL2k and a Documentum 4i e-Content server, and a Tomcat based admin site for the testing environment at the same time. With 1G ram, there was no problem. The host os (xp) wasn't so slow, and the VMWare server instance can serve the requests... So, IMHO you can do any developer work with these systems

Buying a "big" brand notebook (IBM, Sony, Toshiba, Dell) is maybe a better choice if you want to use linux, because these laptop's have better support by the linux community, and there are a lot of stuff written for these systems. But before you buy anything check out this site:

http://tuxmobil.org/mylaptops.html

Lot of howto and guide can be found there...

bye,
kevin