AMD Cool & Quiet – how to do it right

Wed, 2007-07-18 13:38 by admin · Forum/category:

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AMD has issued a technology they call Cool & Quiet for their newer processors. The idea is to reduce their speed and core voltage when their full power is not needed, i.e. when the CPU load is low, and thus to reduce the cooling requirements significantly.

Note that these programs cannot and should not remove the cooling noise when cooling is actually needed, i.e. when you have load on the CPU.

In my tests on several computers with Athlon 64 X2 4800+ processors this technology indeed fulfilled its promise to keep them cool & quiet. However, I was tempted to rename it "Cool & Slow".

The problem

What I found was that the processor ran some 30% slower when the processor load was actually quite high. I found this utterly surprising, because it would be very simple to design the rules such that, as soon as any significant power is drawn, the processor could be made to run at full speed. I don't think that anybody would buy a 4800 processor, only to have it permanently slowed down to somewhere between 3000 and 4000.

To be fair, if you have a task that requires 100% processor load without any deterrent like disk access, then the processor is indeed run at full speed. The problem is that such tasks are exceedingly rare. A much more typical benchmark is video processing, which has high processor load plus regular disk access. That is where Cool & Quiet fails and becomes Cool & Slow.

The technology is based on a driver, which you can download from AMD's web site. This driver regulates speed and voltage, depending on processor load. However, you cannot adjust the rules. Either you install the driver or you don't.

I was asking myself how this could have come about. Were the Cool & Quiet makers stupid? But usually engineers, who invent microprocessors, aren't so stupid. What could be behind this?

The answer is fairly obvious. If you reduce the performance, you raise the demand for more.

The solution

Fortunately ...

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This is a ear-and-wrist-saver!

Tue, 2008-07-15 03:43 by vick233j

My wrist were getting cooked while the noise from the fan was driving me insane. Finally manage to clear up the vent from a ton of dust but still need to undervolt it for the sake of sanity and peace.

My CPU - AMD Turion(TM) 64 Mobile Technology ML-40 has 4 PST including the max and the min. Do I have to adjust the middle two to their lowest voltage?

My CPU has 2.19GHz but my max on the data sheet is 2000MHz. I actually tried adding another PST, increasing the Max PST to 11x. Prime 95's Torture test came back with 1 warning. Shall I keep it or just be satisfied with 2000MHz?

I wasn't able to get to Picture 4 of your instructions with the version 2.35 but somehow I was able to work on adjusting the voltage. I just don't know what else is needed.

Intermediate voltages

Tue, 2008-07-15 14:09 by admin

No, the middle PST (P-State, Performance State) levels have to use intermediate voltages. RMClock will interpolate them for you, but that's a very crude method. You should find those voltages in the processor's technical documentation, which is available on AMD's web site, but a bit difficult to find.

If you overclock the processor, but get a warning, you have two ways to proceed:

  1. Don't overclock.
  2. Raise the core voltage.

Consider that just one test, even a long one, will not make sure that the processor will always work at that speed. You would have to test it at its highest expected temperature, i.e. on the hottest summer day, at continuous full power on all cores.

If it's only the noise of the processor cooler that disturbs you, just buy a better cooler. My recommendation would be a Zalman CNPS-9700 cooler for very high performance or a Scythe Ninja or similar for still fairly good performance at a lower price.

Make sure the processor cooler is temperature-controlled by the motherboard and check the BIOS settings. Aim for a higher processor temperature.

I apologize

Tue, 2008-07-15 15:28 by vick233j

My CPU is in a laptop so the recommended coolers will not work. I apologize for the misunderstanding.

Is there a significant difference in performance if I don't max it out to 2.19GHz? and what is the highest acceptable processor temperature. I think I've only seen mine gone up to about 70 degrees Celsius.

No problem

Tue, 2008-07-15 17:04 by admin

For almost all practical purposes the 10% difference in processor speed is unnoticeable.

I also don't overclock. I don't think it's worth the trouble, unless you have a very good reason.

The maximal processor temperature is very different for different processors. You have to find it in the processor's data sheet.

95 degrees celcius

Wed, 2008-07-16 15:32 by vick233j

That's the Tdie (whatever this is) Max. If it ever gets higher than 55 my wrist will not be able to rest on the laptop, what more at 95. I was able to keep it peacefully at 2.19GHz at 1.2500V but if I keep it at 2GHz, it'll work problem free at 1.125V. Do I have to do anything in the Advanced CPU settings?

Advanced CPU settings

Wed, 2008-07-16 16:53 by admin

I don't know the latest version of RMClock and cannot tell, but probably not.

If you want to keep the temperature very low, don't overclock and keep the core voltage low too. I run my desktop computer undervolted, rather than overclocked, because I like it cool and quiet.

Feeling stupid...

Wed, 2008-01-16 12:31 by Eelco

Hi there!
I've read your article and tried to fix the CPU-RM to my needs (I have an Acer E300, with apparently an AMD Athlon64 3400+ in it).
However, when I check the suggested link in your article, to the AMD site (,,30_182_871_970...), then I can't seem to pinpoint my exact processor. To my untrained eye, there are about 4 processors called AMD 64 3400+.
According to the RM-Memory Analyser-info utility, I have a L2 Cache of 512 KB.
Even then, I can't seem to grasp the settings that I have to make in CPU-RM (I just downloaded the latest version (2.30.1 - build 2007/09/22). The defaults seem to be that all the VID's are at 1.450V...
Could you please help me out here?
Kind regards, Eelco de Vries

Typical problem

Wed, 2008-01-16 14:34 by admin

Don't worry, it's not you who is stupid, but the AMD people who make it so difficult to identify their processors. I also had this problem.

Don't even try the default voltages. In the very worst case and with some bad luck you could even kill the processor. For the lower speeds the voltage should go down towards something like 1.1 V.

Can you look at the processor? It has some imprints that could help. But I guess your processor is somewhere deep inside the computer and you don't feel like ripping everything apart.

Have you tried the AMD CPUInfo tool? Perhaps that yields a good identification. The download is on the page you mentioned.

A very nice thing is that RMClock allows you to test some settings without saving them. So if your computer stops dead in its tracks, you just reboot and go back to the previous settings. The idea is to test the settings thoroughly first, and only if you have assured yourself that they work, you save them.

Wish I could help you, but I can't. What you can do is find out from the manufacturer of the computer exactly which processor you have. Check the computer's specifications, if available. The other way, which you have already begun to go, is to find out some parameters, like the L2 cache size, to identify the processor. Check also whether the speed and voltage figures are similar for the processors in question.

Another method you can use is to undervolt the processor until it stops working. That should give you an idea of how far you can go.

Good luck, and if you find out any better way to get at the correct voltages or the processor identity, please report back here.

AMD Cool'n Quiet / RM Clock

Wed, 2007-10-10 20:14 by DamienO (not verified)

I've read your article " AMD Cool and Quiet", due to my own fan speed problems. I was wondering if this program is for AMD only? (i'm using Intel Core 2 Duo) I'm trying it out myself (a newer version), but it doesn't seem to do the trick. My CPU load is somewhere between 40-60 %, and the fan speeds up just browsing the internet. My computer is brand new, so I find this really strange!

Reduce CPU load

Wed, 2007-10-10 20:51 by admin

Hi Damien,

don't misunderstand the programs RMClock or AMD Cool&Quiet. Their purpose is to lower the clock speed when there is no CPU load, so they cannot help you before you remove the cause of the CPU load.

So what can you do instead? First use Task Manager to find out which process is hogging the CPU. Then try to find out why it is doing that and whether you want it to run. It may be a part of Windows or a virus infection.

Task Manager may not be good enough for the purpose. You may have to download and install a suitable process viewer from Microsoft Sysinternals to find out the truth.


My Task Manager says my cpu

Wed, 2007-10-10 21:00 by DamienO (not verified)

My Task Manager says my cpu load is 5-8%, while RMClock says my CPU load is 40-60%.. so I need another program to find the cause. Could you make a recommendation? There are several to choose from, from Microsoft Sysinternals..

Process Explorer or Process Monitor

Wed, 2007-10-10 22:10 by admin

I've used the old Process Explorer, which would certainly do what you want.

I have heard though that the new Process Monitor does it too and has more options. If you try that, please report back whether it was useful.


2007-04-28 – Griga wrote:

Wed, 2007-07-18 13:42 by admin

Thanks for your great article on Very helpful!

However, there is one point, "The program runs only when somebody is logged on locally."

... not necessarily, I'd say. On my PC RMClock runs quite happily if nobody is logged on, and even if someone is logged on in a limited user account, though the FAQ says it's not possible.

Using the Windows Task Scheduler for launching RMClock at start-up as a kind of background service does the trick. Of course the task must be set up with admin rights, but it is not attached to a particular desktop resp. active user account in this case. Which means, there is no way to access the running RMClock instance, except by stopping the task (by right-clicking it in the Scheduled Tasks folder). So RMClock must be configured very well beforehand!

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