# Pls share your experiences from CPU freq. scaling

## MasterX

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

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## Gherald

 *MasterX wrote:*   

> I am thinking of buying a laptop (any good recommendation?)

 

The IBM Thinkpad X40... costs around $1800, weighs only 2.7 pounds, and claims to offer 7.5 hrs of battery life if you get the 8-cell.

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## nenn

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  :Very Happy: 

```

  GNU nano 1.3.4           File: /usr/bin/speedup                               

#!/bin/bash

echo 1800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq

echo 1800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

echo 1800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

clear

```

nifty little bugger and it works fine  :Very Happy: 

good luck

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## eric_42

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.  :Cool: 

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

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## Gherald

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

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

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## MasterX

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.

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## MasterX

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.

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## Gherald

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   :Smile: 

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## MasterX

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?

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## Kow

What CPU/certain setups support frequency scaling?

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

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## Gherald

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

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## MasterX

 *freeix wrote:*   

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

 

No, I do not think so. All laptops come with Xp, which does not have this capability.

I am thinking of either buying a P4-M or a Centrino. If this CPU freq. scaling can reduce the energy consumption then I will go for the more powerfull P4-M, else I will go for a Centrino

At the following link 

http://www.tomshardware.com/mobile/20030205/centrino-07.html

they test two laptops: a P4-M with a 59Wh battery and a Centino with a 49Wh battery.

Regarding the battery life they found the following:

http://www6.tomshardware.com/mobile/20030205/centrino-17.html

Do you believe that a power management will have any effect on these values? Have you tested it?

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## Gherald

 *MasterX wrote:*   

>  *freeix wrote:*   Was this laptop doing automatic power management during those 2.6 hours? No, I do not think so. All laptops come with Xp, which does not have this capability.

 

Uhh.. hate to break it to you, but XP has great out-of-the-box power management.

It can be surpassed by a fully tweaked linux system, but only after considerable time and effort configuring things.

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## MasterX

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

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## kevin_s

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  :Smile:  )

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

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## kevin_s

 *MasterX wrote:*   

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

 

Hmmm... I forgot it... 

I checked this. Without PM my notebook's runtime is about an hour. With the new 2.6.10 kernel and some custom tweak, the runtime is about 4-5 hours... But this is a centrino system. With a P4-M you never archieve 4+ hours uptime.

bye,

kevin

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## MasterX

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

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## servo888

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.

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## MasterX

 *servo888 wrote:*   

> 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.

 

There is a catch, however. When the CPU works at 800MHz it takes more time to do a certain task, i.e. to open a program to compile a file. So, as long as the task that are running do not need a lot of CPU power, then you are fine and you should save energy, although I did not see this on my desktop.  :Evil or Very Mad: 

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## kevin_s

 *MasterX wrote:*   

> 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.
> 
> 

 

Centrino is very impressive under 1.7GHz too. I have a 1.4Ghz Pentium-M, and the overall feeling of the system's performance is comparable to a 2.5 GHz normal P4 system. 

I read a test when the Dothan cpu comes out. They compare the performance of the 2Ghz Dothan with the P4 3,2 EE and the Athlon64 3200+. (The fastest processors from both manufacturer at the time of the article was written) With certain tasks (divx encoding, office use etc) the performance was comparable. Then the guys tune the dothan a little bit, raise the cpu's freq to 2,3-2,4 GHz (with additional cooling ofcoz) in this config the dothan beats the other CPU-s in 8/10 tests... I think is very impressive. And in normal circumstates the cpu eats only 21 watts...

So, for me this is not a question. There are no real alternative in the mobile environment to the Centrino plattform. Simply no other config can produce this performance with this battery time. I really love this plattform  :Smile: 

But you are right, above 1.7GHz the cpus are lighting fast. I'm planning to replace my note with a newer one, with a 1.8GHz or 2GHz P-M processor.

bye,

kevin

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## Gherald

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.

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## MasterX

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

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## kevin_s

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

bye,

kevin

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## MasterX

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)

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## kevin_s

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  :Smile:  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   :Smile: 

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

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## MasterX

Thank you for the info,

the problem with the big memory is that it is expensive. The ask about $200 for extra 512MB.

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## Gherald

I payed $276 for 1gb of pc2700 laptop memory (this was at newegg.com)

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## Travers

Mine is a HP Pavilion zv5000. I just use shell scripts to change /sys/devices/system/cpu/cpu0/cpufreq*

The only problem I really anticipate with linux+laptops is the wireless card. If you can get one with a linux supported chipset, go for it. The ndiswrapper route is painful [plus no rfmon=no wep cracking =(] despite nidswrapper being a great program. Hard-buttons won't work, but there are programs to assign things to them. Touchpads should usually work out-of-the-box as well.

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## Lepaca Kliffoth

I'm on an Asus L3000D. I'm running on some experimental patchsets like nitro and morph (kernel 2.6.10) and I use the ondemand governor, mainly. What it does is polling automatically to see how much cpu power is required and scales the cpu frequency (athlon XP-M) accordingly. Works flawlessly. When I know I need max speed I just switch to the performance governor. It's working very well and the power consumption goes down a LOT when the cpu is scaled down to the minimum allowed - e.g. the power supply heats much less while you almost can't keep it in your hand when everything's going full speed.

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## Ecco

On my Sony VAIO (Centrino 1.6) I use 'ondemand' when I use AC, and it switches to 'powersave' when running on battery power (in my case 600MHz). 

This increases my battery life significantly. ACPI is great!

What also helps btw, is not running a cron daemon or a system logger. All that harddrive access eats battery power too. You don't nead it on a laptop anyway.

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## MasterX

 *Ecco wrote:*   

> 
> 
> What also helps btw, is not running a cron daemon or a system logger. All that harddrive access eats battery power too. You don't nead it on a laptop anyway.

 

Then you need to run updatedb manually. You need this command for sure. 

You might not need cron daemon but I think that you need a system logger, if you want to know what is happening to the system. Maybe you can tweak it so that only critical informations are written and not everything. Lets say it what happened and the system crashed.

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## Ecco

 *MasterX wrote:*   

> ...
> 
> Then you need to run updatedb manually. You need this command for sure. 
> 
> You might not need cron daemon but I think that you need a system logger, if you want to know what is happening to the system. Maybe you can tweak it so that only critical informations are written and not everything. Lets say it what happened and the system crashed.

 

You want the cron daemon to run updatedb for you? I don't even do that on my workstation   :Confused:  It hasn't been that long since gentoo added this by default, and it was the first thing I switched off again.

Like you said: when you need it, if you ever need it, run it yourself. On a laptop that's running on battery power you really don't want these things to run on their own accord. And no, you most definately do not need a system logger. You may want one for the workstation you like to fiddle with to find out what's happening, but I certainly do not need one for my laptop. I don't use my laptop for fiddling, I need my laptop to just work.

And it does: From the moment I switch it on I have a working desktop (xfce4) in 42 seconds flat. There is as good as no harddisc activity when I'm not doing anything. The battery lasts nearly 5 hours (with a VAIO screen!). It has everything I need, and always works.

I love my VAIO  :Very Happy: 

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## Gherald

My father has a VAIO... I had to use it once.  The keyboard was absolute CRAP.  I couldn't stand it at all and ended up connecting a spare dekstop keyboard.

But I guess I'm spoiled by my thinkpad.

For people concerned about a syslog causing disk access, emerge metalog.

In /etc/metalog/metalog.conf you can easily specify the minimum number of log lines to cache before they actually get written to disk.

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## MasterX

Correct me if I am wrong, but even if you do not have a system logger, the daemons (e.g., cups ... do not ask me why you need this running -> This is a hypothetical question) will create their log files, and the only thing that a logger does, is to "rename" these files. Without this "renaming" we would have a BIG and propably unreadable log file. So, you do need a system logger and I will agree with freeix that it needs some tweaking.

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## Gherald

Well here is one idea: https://forums.gentoo.org/viewtopic.php?t=284995

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## Ecco

 *MasterX wrote:*   

> Correct me if I am wrong, but even if you do not have a system logger, the daemons (e.g., cups ... do not ask me why you need this running -> This is a hypothetical question) will create their log files, and the only thing that a logger does, is to "rename" these files. Without this "renaming" we would have a BIG and propably unreadable log file. So, you do need a system logger and I will agree with freeix that it needs some tweaking.

 

It won't log kernel messages, but you're right about the rest. Logs will still be written; only I don't run anything that needs logging on my laptop (what do you run on a laptop that needs logging? I sure couldn't find anything). So no, they don't get big, and they don't get out of hand. In fact, they don't exist. There's only xorg that writes a significant amount in it's log when starting, but he just backs up the old log and starts a new one everytime he loads, without the help of any system logger at all.

You may use metalog and strip it down to having nearly no harddisk access, but it'll basically do the same as not running it at all, so why bother?

And freeix, I'm not even going to respond to that dumb ass flame  :Rolling Eyes: 

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## Gherald

If your particular VAIO has a better keyboard, I wouldn't mind hearing about it.  I just know this model has the absolute worst laptop keyboard I have ever used.

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## Ecco

 *freeix wrote:*   

> If your particular VAIO has a better keyboard, I wouldn't mind hearing about it.  I just know this model has the absolute worst laptop keyboard I have ever used.

 

It must have a completely different keyboard than they put in other (bigger?) laptops. I seriously have never typed on a more wonderful keyboard than on my laptop. Other people always tell me the same thing when they use my laptop. A friend of mine who owns a VAIO has the same experience with his. So if the above mentioned keyboard is horrible, I think it's probably an exception.

Mine is this one btw.

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## Gherald

I suppose Sony must mix and match from various ODMs... I don't like that kind of company, it makes you have to evaluate every single model independently.

What's funny is the page linked from there lists Sony as having 2 primary ODMs, whereas for IBM there are 3.  But /their/ models really are consistent across the line, so once you've decided you like Thinkpad keyboards  (an easy decision to make, if you've ever tried Linux on one!), you can rest assured that any model you choose will have the same great kb.

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## Ecco

 *freeix wrote:*   

> I suppose Sony must mix and match from various ODMs... I don't like that kind of company, it makes you have to evaluate every single model independently.
> 
> Whereas IBM models are consistent across the line, so once you've decided you like Thinkpad keyboards  (an easy decision to make, if you've ever run Linux on one!), you can rest assured that any model you choose will have the same great kb.

 

They don't; almost everything is manufactured by themselves. If you're seriously interested in VAIO's compared to other notebooks; use google. But you're not. In fact I'm starting to think comparing notebooks is some phallic competition to you, and I've got better ways to spend (waste) my time. Enjoy your thinkpad  :Smile: 

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## Gherald

 *Ecco wrote:*   

> They don't; almost everything is manufactured by themselves.

 

Then they themselves are subject to the full brunt of my aversion for manufacturing a system with such a crappy keyboard.

 *Quote:*   

> If you're seriously interested in VAIO's compared to other notebooks; use google.  But you're not.

 

Doh, I personally am not interested in "VAIO's" seeing as I  have already made my decision and plan to keep this thinkpad for years to come.  But to the OP and anyone else looking to make a purchase decision, I am simply explaining that IBMs are widely regarded to have /the best/ keyboards, and that Sony has made at least one crappy one.  That is the extent of my knowledge on the matter.

Additionally, telling me or anyone else to use google in comparing "VAIO's" to other notebooks is hardly helpful seeing as no one here has demonstrated that level of ignorance.

 *Quote:*   

> In fact I'm starting to think comparing notebooks is some phallic competition to you

 Not really.  In fact I happen to just be making a recommendation based on personal experience, rather than wasting my and everyone else's time with silly commentary.

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## Ecco

 *freeix wrote:*   

> blah

 

That's right, you judge an enormously wide range of laptops by the fact that your only encounter with one of them involved a crappy keyboard. Ignoring the entire fanbase of VAIO users, not to mention all the VAIO owners who happily run linux on their laptop (surprise: linux runs fine on just about every laptop). Way to spread out information.

I never even posted to tell the TS he should buy a VAIO, I just said I was happy with my one. The first thing you do is make some shitty, flaming remark that helps absolutely nobody except your little ego. Feel proud of yourself. This conversation is over.

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## Gherald

 *Ecco wrote:*   

> That's right, you judge an enormously wide range of laptops by the fact that your only encounter with one of them involved a crappy keyboard.

 

Sorry, but you are imagining things.  I never judged the whole range except to point out that if you get a thinkpad you can be spared the hassle of trying to find out whether a particular model has a decent keyboard.  Moreover, you can rest assured any thinkpad will have /the best/ keyboard available.

 *Quote:*   

> Ignoring the entire fanbase of VAIO users, not to mention all the VAIO owners who happily run linux on their laptop (surprise: linux runs fine on just about every laptop)

 

What does that have to do with anything I said... other than the obvious fact that Linux users should be concerned about keyboard quality?

 *Quote:*   

> . Way to spread out information.

 

There is nothing wrong with me relating my knowledge that 1 VAIO has a crappy keyboard.  If people want to know how good the keyboards are on particular models, they are free to look that up.  By contrast, if they get a Thinkpad, they won't have to worry about keyboard quality and can concentrate on other specs which tend to be less subjective, more standardized, and more readily available.

bye

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## MasterX

Here are a couple of questions:

1) You said that Xp has a good power management. The only thing that I have seen on a XP machine is "turn off the monitor" and "turn off the harddisk". Is this the power management you have been talking about? Can XP control the freq. of the CPU?

2) Lets say that you have a laptop with a P4M at 3GHz and you are watching a DVD. I believe that it won't take more than 10% of the CPU to play the DVD. 

Now, we scale the freq. of the CPU down to 1GHz and you continue watching the DVD. Because of that change in the CPU freq. now 30% of the CPU is used.

The fact that we decrease the freq. of the CPU will cause the energy consumption to decrease, but what is the effect of the percentage of the CPU being used? If I use 10% or 30% of the CPU does it make any difference?

3) Finally, if the CPU has HT, would it consume more energy if this enabled or it does not make any difference?

Thank you

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## Gherald

Yes XP can control the frequency of the CPU more easily than linux, and it comes pre-configured this way on most if not all Laptops.  Microsoft, Intel, Dell et. al. have a very good working relationship.

Try going to the Control Panel --> Power Management on a Laptop with XP.

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## brodo

 *MasterX wrote:*   

> 
> 
> 2) Lets say that you have a laptop with a P4M at 3GHz and you are watching a DVD. I believe that it won't take more than 10% of the CPU to play the DVD. 
> 
> Now, we scale the freq. of the CPU down to 1GHz and you continue watching the DVD. Because of that change in the CPU freq. now 30% of the CPU is used.
> ...

 

Yes, in a highly complex way: the power consumption varies between:

CPU at full speed and working

CPU at low speed and working

CPU idle at full speed, and even dependant on the duration of it being idle

CPU idle at low  speed, and even dependant on the duration of it being idle

Approximations for this on a Pentium M 1.4 GHz (Banias):

1.4 GHz, working: 22 W

600 MHz, working: 6 W

1.4 GHz, idle: 0.55W to 7.3W depending on idle mode (ACPI C-State)

600 MHz, idle: 0.55W to 1.8W

(Intel(R) Pentium(R) M Processor Datasheet, Order Nr. 252612, rev. 02, June 2003, p. 72.)

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