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AMD Cool & Quiet – how to do it right

Copyright © 2006-2010 Hans-Georg Michna



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 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 our Russian friends from cpu.rightmark.org are coming to the rescue. The well-known makers of benchmark and other computer test programs also have a much more refined processor clock regulator named RMClock.

This program does the same as the AMD "Cool & Quiet" driver, but without the huge performance loss of the AMD driver. You get the best of both worlds—a cool processor like with the AMD driver, yet maximal performance when there is any demand for it.

I see only two shortcomings of RMClock.

  1. The program runs only when somebody is logged on locally. This is alleviated by the fact that computer noise doesn't hurt much when nobody is sitting at the computer. (But see the chapter "Additional information" below, near the end of this page.)
  2. The documentation is sparse and written by engineers for engineers.

This page is trying to fill in the missing information and to make it a less daunting task for the rest of us.

The program can do almost everything you could ask for, but it demands that you enter some critical data by hand. Some of this data is critical enough that you can easily halt your processor or in some extreme cases even destroy it. So be a bit careful when you install the program and set it up for the first time. But if you like to have a cool & quiet & fast processor, read on.

If you had already installed AMD's Cool & Quiet driver, uninstall it and reboot your computer. That driver misleadingly calls itself, "Windows Driver Package – Advanced Micro Devices (AmdK8) Processor ..." and is therefore near the end of the Add/Remove Programs list, rather than anywhere near "AMD" or "Cool & Quiet".

Download RMClock from cpu.rightmark.org and start it. Go into the settings. Now let's set it up properly.

The following instructions are for version 2.15, but the current version is 2.2 or higher. Hopefully most of the settings are still the same.

First you may have to go to www.amd.com though and find the thermal spec sheet for your processor, because you need to know exactly the permitted speeds and voltages. Click on Processors, then on the name of your processor, then on Technical Documentation and find, for example, the AMD Athlon™ 64 Processor Power and Thermal Data Sheet.

In the document find the table of permitted speeds and the respective core voltages. You will have to enter these into the RMClock settings.

But first let's look at the general settings and set them as shown, unless you have a good reason for a different setting. The following example is for the Athlon 64 X2 4800+ processor.

After entering the settings on each panel, click on the Apply button.


Picture 1 – General settings


Picture 2 – Management settings

The settings "Use OS load-based management" and "Run HLT command when OS is idle (restart required)" are normally unfavorable and therefore not recommended.

Thus the settings as shown above are recommended, with one exception. Deselect the last one, "Run application automatically when Windows session starts" for now and leave it off for a few days. Start the program manually each time you log on. This has the big advantage that some unsuitable setting is not applied automatically and thus cannot kill your computer every time.

Only after you have observed the behavior of the program for a few days and are completely satisfied that all is well (no blue screens, no freezes, no inexplicable errors), you can finally enable this last setting.


Picture 3 – Profiles

Picture 3 shows how you have to select the permissible frequency multipliers (Frequency ID = FID). The multipliers refer to a base frequency, which, in the case of the Athlon 64 X2 4800+, is 200 MHz. This means that 4.0x translates into 800 MHz, 5.0x is 1,000 MHz = 1 GHz, and 12.0x is 2,400 MHz = 2.4 GHz, the highest speed of this processor.

Note that the processor in our example, the Athlon 64 X2 4800+, doesn't use the 1,200 and 1,600 MHz speeds, and particularly not 800 MHz. If you ignore this and enable 800 MHz (FID = 4.0x) on an Athlon 64 X2 4800+, then the processor will instantly halt when you click on the Apply button, because it cannot actually run at 800 MHz.

Fortunately the program is clever enough not to save those settings when you apply them. It saves them only when you explicitly close the program, which is a clever way to keep you out of trouble, because now all you have to do is to press reset or cycle the power on your computer, and it will come up again without using these settings.

In any case, your best choice is to enter the correct settings for your particular processor.

In my version the first attempt at entering the settings in this pane failed consistently. I always had to enter them a second time, when they finally stuck. So after entering and applying them, go to another pane, then return here, recheck and, if necessary, enter the settings once again.


Picture 3a – Undervolt settings

Picture 3a shows settings with voltages below specification. This is the opposite of overclocking. You could call it undervolting.

Since these settings do not comply with the specifications, you have to test them carefully and thoroughly before you keep using them. If they work, they will keep your computer somewhat cooler and quieter than the correct settings, but be careful and test thoroughly.


Picture 4 – Performance levels

The next step is to actually activate the transitions and all power states you like to use. Click on the little plus sign to the left of Profiles and go down to the Performance on Demand settings. You can safely ignore the other ones. Then choose to Use P-State Transitions (PST).

In the little table that follows you can again select the different P states. The least you want to check are the lowest and the full performance ones, but my recommendation is to allow all of them. You will only have a choice for those that are already allowed in the profiles pane.

Then comes your most important choice, the one that's totally missing from AMD's Cool & Quiet driver—the performance or power saving level. Here my recommendation is Performance Level 5, which gives you about 98% to 99% performance, while still keeping the processor cool when its load is low. This is a setting where you get full power when the processor load exceeds some 15% to 20%. Remember that 50% is already full load for one of the two processor cores in a dual-core processor, and many programs cannot use both processors at once.

If you want full speed already at processor loads around 10%, choose the maximal Performance Level 7. On the other side of the scale are the settings that keep the processor cool at the cost of not getting its full performance. I don't see much sense in those settings, but at least they are there, should anybody want them for any reason. Compare this to the AMD driver, which always uses a most unfavorable setting.

Now hold your breath and click on Apply. Does your computer still run? Then what you've done was at least not totally wrong.


Picture 5 – CPU setup

Now we get to the last pane with three tabs, where we want to enter a few settings. Leave them all at their defaults or click on the Defaults buttons to reset them.


Picture 6 – P-states transitions

Leave the P-States Transitions at their defaults as well, but you can elect to use the more conservative AMD P-State Transitions Rules to stay within AMD's specs. You will hardly lose much performance here, because with our settings the transitions are relatively rare. In particular, you will experience almost no transitions at all when there is any higher processor load, as the processor will then stick firmly to its highest speed.


Picture 7 – Misc control

On the last tab you can select the core thermal sensor. If both sensors are working properly and show similar temperatures, then it does not matter which one you choose. The other setting is rather special. Set it as shown, unless you use the AMD Dual-Core Optimizer. (I don't even know what that is.)

Click on Apply one last time and check whether your computer is running nicely and without problems. If so, close the RMClock program entirely. Close the settings window first, then right-click on the sprocket icon in the system tray (System Notification Area in newspeak, usually in the lower right corner) and select Exit RMClock Utility. Now your settings are saved and will be applied automatically the next time RMClock is started. Note that the settings are not applied when nobody is logged on to the computer, because then the program is not loaded. (But see the chapter "Additional information" below for solutions.) Unfortunately this program does not exist as a service, only as a normal application program.


Note how the fan goes down to lower rpm and the processor cools when RMClock is active and set up properly. If you have no indicator for it, right-click the RMClock sprocket icon again and select the following two settings:

This gives you a speedometer in the form of a progressive red ring on the sprocket, as your processor speeds up, as well as a temperature gauge next to it.

Remember that you have to close the program once to make it save the new settings.

Enjoy the silence and the speed and be grateful to your new little Russian helper!

By the way, this is not the only Russian software that I have come to like. Programs like WinRAR, Acronis TrueImage, Parallels, or Abby FineReader all have Russian roots, and their quality is mostly excellent.

I'm grateful for a comment (click here, then click on Add new comment), if you find any errors or omissions or if you have any proposals for the improvement of this web page.

Copyright © 2006-2010 Hans-Georg Michna

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