CrystalCPUID: User Configurable Cool 'n' Quiet

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Now that we have run Prime95 to verify that the system is stable at the default AMD state, which in this case is 1000 MHz (5x) / 1,100 V. Start CrystalCPUID and open the "K6/K7/K8 Multiplier" menu (Ctrl-K). Begin lowering the voltage, Prime95 should still be running Torture Test in the background. Drop one step (0.025 V) every five minutes until Prime95 detects an error. It is possible that you will bottom out with the voltage settings, 0.800 V being the lowest one A64s support. Run the Torture Test for at least 12 hours (I highly recommend 24 hours) to determine stability at this state.

If Prime95 detects an error, bump the voltage one step up, and restart the Torture Test. Continue until you manage to run at least 12 hours without errors. If no errors are detected after 12 hours, you have found the lowest stable settings for the Minimum state. Record them somewhere.

Next, set voltage to 1.400 V and multiplier to 9.0x. Again, while Prime95 Torture Test still running in the background, begin dropping the voltage. Drop one step (0.025 V) every five minutes until Prime95 detects an error. Then, bump the voltage one step up, and restart the Torture Test. If Prime95 still detects an error, bump the voltage another step up. Continue this until you manage to run 12 hours without errors. Then you have found the lowest stable settings for the Middle state. Record them.

As you already might have figured it out, the same process still needs to be done to determine the Maximum state. Set voltage to 1.500 V and multiplier to 10x, and redo the steps mentioned above. This will get you the settings for the Maximum state.


Now all that needs to be done is to enter the state information to the multiplier management menu, and make a shortcut so that CrystalCPUID starts automatically on startup.

The author of the utility refers to Multiplier Management as "Crystal 'n' Quiet" in the readme txt file.

Entering the multiplier/voltage values should be quite straightforward. Determining the Up/Down thresholds is a bit more problematic depending on the selected multipliers. As a rule of thumb, multiplier/performance function can be assumed linear, e.g. running at 100% load at 1 GHz corresponds to running at 50% load at 2 GHz.

In other words, setting the Down Threshold for 2 GHz to 1 GHz transition to over 50% will cause a situation where the CPU load after the transition is 100%; thus the state changes back to 2 GHz, which then again drops the load under the Down Threshold, and the cycle repeats. In the long run this might damage the motherboard. Adding the Middle state and the possibility to jump over the Middle state in the transitions makes the threshold setting more complex.

The Interval Times affect the respond rate to state transitions. CPU load is polled once per Interval Time, so e.g. if the Interval Time of the Minimum state is set to 5000 ms, a random CPU load peak (for instance, starting a program) might be undetected. Depending on the situation this might not be a bad thing, though.

With Multiplier Management enabled, hardly anything changes in the main window. Note the CPU load percentage in the title.

After this configuration, Crystal'n'Quiet is ready to use. In the main window, press F3 to enable multiplier management. Current CPU load will be shown in the title bar, and the tray icon shows the current state (if you checked "Colorful Icon" in the settings). Pressing F4 in the main window opens real time CPU Clock. Leave it open to see how the speed changes during normal operation. Left-clicking the CrystalCPUID's tray icon hides the main window. BE SURE NOT TO CLOSE THE WINDOW FROM THE CLOSE BUTTON, since this will shut down CrystalCPUID.

I strongly advise that you test the stability of the system thoroughly before making CrystalCPUID start automatically on startup. So, use the computer as you would normally, might it be browsing the web, playing games, [email protected], watching movies, playing music, etc.

If you start CrystalCPUID normally from the shortcut, it just opens the main window without enabling Crystal 'n' Quiet. What needs to be done is to add two command-line parameters to the shortcut. Open the properties of the shortcut (right-click). Add following to the end of the Target-field (without the quotation marks): "/hide /cq". Click Apply, OK and you're done. Shut down CrystalCPUID and test the shortcut. If it works properly - main window doesn't come up, and tray icon changes to indicate current state ("Colorful Icon") - move it to the Startup-directory in Start Menu.

You can easily disable Multiplier Management temporarily by just right-clicking the Task Bar icon, and de-selecting "Multiplier Management". By doing so you'll automatically enter the selected "Exit Mode" state. The "Exit Mode" state can be configured from the setup window.


After reading this article it should be clear what CrystalCPUID can and can't do. It doesn't show any temperatures, nor does it control any fans. CrystalCPUID just changes the multiplier & core voltage of the CPU according to the CPU load. Temperature measurement support and fan speed control have to come from optional programs and/or devices, such as SpeedFan or fan controllers. There is at least one alternative to CrystalCPUID that I know of - RMClock. I can't tell any personal experiences about RMClock since I haven't tried it out... yet. (Editor's Note: SPCR reviewers Ralf Hutter and Russ Kinder had a go with RMClock a couple of months ago and found it to be highly unstable at the time, on AMD and Intel platforms.) At this time, there does not appear to be an equivalent utility for Linux users, who have to resort to modifying the kernel code/driver to attain similar functionality.

CrystalCPUID's configuration process is very time-consuming, but the rewards are beneficial. On my computer, while running at 2 GHz, I was able to drop the voltage from 1.5 V to 1.3 V. This in turn dropped CPU full load temperatures from 57°C to 47°C. This result cannot be achieved with Cool 'n' Quiet.

My motherboard (MSI K8N Neo) is able to control the voltage of the CPU fan. With the help of SpeedFan I managed to run the CPU fanlessly during normal use (with a Zalman CNPS7000-AlCu as the CPU cooler), and the temperature never exceeded 45°C. SpeedFan was set up to start the fan whenever temperature exceeded 50°C, which occurred rarely (games or compressing archives). I used the Zalman Fan Mate to limit the fan's voltage to 5V at all times while it was on.

With my current setup there is no audible benefit in running the CPU (nearly) fanless, so I let the CPU fan spin at 5V all the time. Whenever I'm not doing anything processor-intensive — about 96% of the time! — the system idles at 1 GHz and 0.85 V, while the CPU is comfortable at 30°C. Yet, all the number-crunching power of the A64-3000+ automatically kicks in when it's needed.

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As mentioned earlier, CrystalCPUID v4.3 supports the Enhanced Intel Speedstep Technology (EIST) and on-demand clock modulation (ODCM), Intel's dynamic CPU clock / multiplier / voltage management features built into the new Intel 600 series, the 570J, and the Pentium M. We will cover CrystalCPUID operation with systems using these Intel processors in the future.

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