A Guide on Undervolting

Though there are many of useful undervolting guides available at different forums, this new one may happen to be most detailed one.

Undervolting a laptop
http://www.nordichardware.com/Articles/?skrivelse=465

(Tried to post it to the Guides forum, but it seems I have no permission to ).

 

Good find. I will try undervolting my laptop when I get it. I don't think I really need to, because its suppose to get up to 7hrs 15 minuts. That is the max though. But its not only for the battery life also to keep it a bit cooler. Especially when on your lap.

 

Can I use Centrino Hardware Control to achieve the same results with undervolting?

 

I use NHC/CHC - it works well. Check my article here:
http://www.thegamebooks.com/undervolting-intel-pentium-m---how-to-keep-your-gaming-cool-t78.html

I play games at 65-67 degrees instead of 75-77 before. That is two fan speeds down to - so it is quieter.

Cheers,

 

Thanks for the info...I've learned alot reading various articles over the last 12 hours!

Do I only need to set the max and min multipliers/voltages and nothing else in between?

 

THe minimum is all you *need* to set, but the more steps you set, the more efficient (cooler, longer battery) your machine will run, which will enhance the life of both your laptop and your lap.

 

Half a year ago I would say that NHC (then, CHC) is slightly superior.

Then, however, RMClock has introduced tunable intermediate states.
So, if you like to gain a couple of percents more of battery life you can fine tune the intermideate states below the linear interpolation between min and max.

I use RMClock, because I always had some installation problems with NHC (with .NET) when I wanted to test it, and I had a (very) subjective impression that it takes more juice from my lappy.

It was mentioned somewhere that the difference between rmclock and NHC is that one of the programs takes a little bit more memory, and another one the processor resources. I don't remember the details, though.

 

Actually the minimum voltage brings very little temp drop. Maximum multiplier (in my comp it is 14x) brings temp 10 degrees down in games.


Cheers,

 

I tried using that RM clock utility and when I go to managment and try to use Power state Transitions it won't let me. My notebook is a Averatec 6130hs P4 3ghz/HT also it's a Northwood P4C. Since I can't access it does it mean that my processor can't be undervolted?

 

I've been reading some guides and noone mentions if i should have my AC plugged in or not. Anyone know or does it matter?

 

Your Pentium 4 does not have EIST(or Enhanced Speedstep). So there is no possibility of udervolting at anything other than the standard(max) multiplier.

It is better to undervolt when on AC power since many laptops have built in power saving features which slow down the cpu or wont let it go upto its max multiplier.(when you undervolt, you overide these settings).

 

There are also the issues with stable undervolting on AC and BSODs on batt.

I covered most of the problems in this article:
http://www.thegamebooks.com/undervolting-intel-pentium-m---how-to-keep-your-gaming-cool-t78.html

Cheers,

 

Hey Ivan,

Nice post, I liked it. It seems like you are more knowledgable in this area then some of us, so I am going to ask you a hypothetical question about the new core duo processors and NHC: Will it work ?

Also, I am very curious about how someone goes about developing such a tool. I tried searching for source code for NHC/CHC type tools but no luck. Are you aware of any such development community?

thanks

Nick

 

Hi Nick,

I'm flattered, but actually I'm just an ordinary user. I use CHC/NHC for a long time now, and I was fortunate that I tried it on Asus M6N where absolutely everything worked (even fans and disk noise).

I'm not sure about the duo core processors. I don't know how is speedstep implemented on dual core. I reckon that both cores actually "listen" to the same clock. So NHC should work as it controls the clock, not the CPU.

I'm not part of any developer community, and for NHC code I would contact the programmer. I think there are developed drivers for sensors and oscillators (clocks) that can give you readings (access) that can be altered and "put into" particular devices (clock, fan control etc..). Some are just implemented technology that cannot be used from windows settings - for example disk spindown. GPU overclocking seems particulary easy, as there are many tools to do it. Voltages are also handled through some kind of driver that reads some values from a table and applies to the CPU.

How to make such a driver? That is probably the real magic. Very hard work is behind that. The only thing that helps is that more and more manufacturers do their work following standards. The smaller number of devices and their mutual "firendship" will produce more modular, powerful and easier computers for us. Apple is living example. I still hear their hymns about IBM PowerPC and RISC CPUs. Now they are on Intel CISC. And only thing I can say - good for them (and us).

Cheers,

 

Hey Ivan,

Thanks for sharing your ideas.

It's funny, I tried installing NHC on one of my very old desktop systems which I had built like 4 yrs ago. It has an ABIT BP6 motherboard supporting two Celeron socket 370 333 Mhz (oc 533) PPGA processors. Not that it really matters, but NHC combines both the celeron cores and reports them as one.I did this just for the kicks of it.

Anyways, it would be nice if there is an open source community supporting NHC type application particularly for linux. For one thing, we will have more hardware support.

thanks again.

 

Hi Nick,

Yes that is interesting, and maybe just validates my expectation. NHC actually controls the clock, and even on a dual CPU mainboards there is only ONE clock generator. So you change the speed there, and all cores are affected.

If you contact the programmer about the linux (or opensource) tool, maybe he would give you more info.

Cheers,

 

Hello, I'm tinkering with some undervolting on my new laptop to get some more battery life. However, I'm down from .988 to .812 and I'm not seeing any increase. This is on Max Battery profile, so it only uses the lowest multiplier. My computer is in my sig.

Is there some method to undervolting that I am overlooking? I did it on battery power, but did not go very aggressive; and am not having stability problems. Do I need to have NHC run when windows starts to see a battery increase? Or, am I able to just start it up when required (preferred) and have it affect voltage and battery. Thanks for your help.

 

oh i really want to know if there is such programs for linux as the 64bit cpu's and the linux 64bit would benefit from this as well

anyone know?

 

Hi everybody.

I'm running some tests with my new 5672WMLi Core Duo T2300. I'm trying to undervolt since its a little hot. I've tried both RMClock and NHC. neither seem to give the option of chaning the voltages for any of the multipliers or anything. NHC will not even display the default multiplier values.

RMClock cannot detect what kind of Power Management features are available.

I'm using the newest versions of of both programs...dunno what else to do..

EDIT: CPU-Z correctly detects the processor just like the other 2 programs.

 

Since the Core Duo is fairly new on the market, these programs probably need an update to correctly identify them.

EDIT: Seems like sad news in unervolting the Core Duo...
http://forum.rightmark.org/topic.cgi?id=6:500

 

Does anybody have any solutions to my previous undervolting problem? It does undervolt, but I'm not seeing a battery life increase. See above post*

 

Undervolting does not have too much of an affect on battery life. The main advantage of undervolting would be in heat generation. There might be a little increase in battery life in cases where the fan does not turn as often but even then it is quite negligible. You will need to have NHC running in the background if you want the cpu to run at the voltages you specified, otherwise it will run at the default voltages.

 

Thank you! I get decent battery life, but I wanted to experiment. Basically I was just wondering if NHC maybe needed to start with windows in order to effect voltages. I'm still going to use it though, good program.

 

Yes, I agree with Miner. You won't see much battery life improvement when running mostly idle( like web browsing, word editing etc), but when you run CPU as max loads it shows lot of difference( could be as much as 30 min).

In my experience the main advantage of Undervolting is heat reduction. Heat generation is noticably reduced even at low CPU loads and fan won't kick in too often.