Power-Optimizing The Intel Pentium M Laptop

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Introduction/Background

This article will show the owners of Pentium M / Celeron M laptops how to optimize the power management features to get more battery life, less noise and less heat output from your trusty laptop.

I will be optimizing my work-issued Dell latitude D600 1.6 GHz Pentium M laptop as the example. I also give differential information about CPU wattage before and after optimization. Please note that there may be slight errors on these calculations – if someone knows about an accurate wattage calculator for Pentium M CPU’s, please let me know.

From the manufacturer, these laptops come equipped with Intel’s SpeedStep technology. This technology actively changes the multiplier and the applied voltage to the CPU in proportion to the CPU load, positively affecting battery life. When you are writing a word document, etc. your CPU load is low, so the multiplier is lowered to set a lower operating frequency for the CPU and the voltage supplied to the CPU is also reduced. On the other hand, if you are playing a game, etc. the CPU goes back to the original frequency and voltage.

We are going to use the same technology used in SpeedStep, but we will customize it for our unique laptop. Before going any further we need to go to the Start Menu and disable SpeedStep.

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Figure 1: Disabling SpeedStep in W2000: Start ‘Control Panel’ Power Options.

I have Windows 2000 on my laptop – if you have XP, de-selecting SpeedStep tab is not available. The simplest workaround for this is to select the “Always On” power scheme in the Control Panel. This indirectly disables SpeedStep under Win XP and lets Crystal CPU ID do its intended work.

We are going to substitute the native power management features with a customizable program, Crystal CPU ID. Additional third-party software is also needed for checking the CPU settings and stress-testing the system:

  1. Crystal CPU ID
  2. CPU-z
  3. Prime 95
  4. Sisoft Sandra 2005

Run and install all of the above software packages.

You should be able to download them using the links above. Crystal CPU ID is going to be the main program to set our new power management settings and for testing them. CPU-z and Sandra 2005 are going to be used mainly to identify and verify the settings. Prime 95 will be used to stress our CPU to make sure it is 100% stable at the different settings.

Setting the High Multiplier and Voltage

Start with the stock settings for your CPU. Run Crystal CPU ID, click on ‘File’ and select ‘Multiplier Management Settings’.

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Figure 2: Crystal CPU ID’s Multiplier Management Setting Window.

This will be your main working window while you are optimizing your system. Notice the Multiplier and Voltage columns (see Fig. 2 above). Below the Multiplier column there is a button to enable voltage control. Go ahead and click on it to enable voltage adjustments (see Fig. 2 above). Also notice the ‘Option Exit Mode’ selection. You are going to be changing this setting to ‘Maximum’ (see Fig. 2 above). Do not worry about the other options right now, you can go back later and fool around with them.

On the ‘Multiplier Management Settings’ select a lower voltage for the Maximum setting (16x). My CPU had a stock voltage of 1.40volts at 1.6GHz. Go one step down in voltage and then click on ‘Apply’ and ‘OK’ to set your CPU (see Fig. 2). Now go to the Crystal CPU ID icon on your toolbar and right click on it. Go to ‘Quick Multiplier’ and select ‘Maximum’ (see Fig. 3).

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Figure 3: Forcing the multiplier/voltage setting.

This will set your CPU control settings at the maximum multiplier and voltage for the time being while you test your system. Run CPU-z and/or Sandra 2005 to verify the current multiplier and the voltage of your CPU. Now go ahead and run Prime 95 on ‘Stress Testing’ mode for about 15-20 minutes to verify the short-term stability of your new setting.

Keep lowering your voltage and going thru the above process until you get an error in Prime 95. Then go back and set a higher voltage and stress test it again. Once you reach what you think is an optimal setting, run Prime 95 for about 24 hours to make sure your computer will be 100% stable at its new setting.

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Figure 4: Verifying the Multiplier/Voltage settings and stress-testing the CPU.

On my laptop, I was able to lower the voltage to 1.068v at the default 1.6 GHz vs. the original 1.40 volts. In my case, this is a reduction of 10.25 watts from the stock 24.50 watts to the optimized 14.25 watts – a wattage reduction of almost 42%. Once you are sure that it is stable, write down the settings for future reference and let’s move on to set the middle parameters.

Setting the Middle Multiplier and Voltage

Run Crystal CPU ID, click on ‘File’ and select ‘Multiplier Management Settings’. Go to the ‘Option Exit Mode’ selection. You are going to be changing this setting to ‘Middle’.

Then go to the Middle multiplier setting and set it as you please. I used the 11x multiplier on my laptop. Then go to the voltage setting for the middle multiplier and select a voltage for the Middle setting. I used 0.924v as my initial voltage setting for the middle multiplier (11x).

Now go to the Crystal CPU ID icon on your toolbar and right click on it. Go to ‘Quick Multiplier’ and select ‘Middle’. This will set your CPU settings at the middle multiplier and voltage for the time being while you test your system. Run CPU-z and/or Sandra 2005 to verify the current multiplier and the voltage of your CPU.

Now go ahead and run Prime 95 on ‘Stress Testing’ mode for about 15-20 minutes to verify the short-term stability of your new setting. Keep lowering your voltage and going thru the above process until you get an error in Prime 95. Then go back and set a higher voltage and stress test it again.

Once you reach what you think is an optimal setting (no errors after 15-20 minutes) run Prime 95 for about 24 hours to make sure your computer will be 100% stable with the new setting. Once you are sure that it is stable, write down the settings for future reference and let’s move on to set the minimum parameters.
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Setting the Minimum Multiplier and Voltage

Run Crystal CPU ID, click on ‘File’ and select ‘Multiplier Management Settings’. Go to the ‘Option Exit Mode’ selection. You are going to be changing this setting to ‘Minimum’. Then go to the Minimum multiplier setting and set it as you please.

I used the 6x multiplier on my laptop; for some reason, the 7x multiplier did not seem to work on my laptop. Then go to the voltage setting for the minimum multiplier and select a voltage for the Minimum setting. I used 0.812v as my initial voltage setting for the minimum multiplier (6x).

Now go to the Crystal CPU ID icon on your toolbar and right click on it. Go to ‘Quick Multiplier’ and select ‘Minimum’. This will set your CPU settings at the minimum multiplier and voltage for the time being while you test your system. Run CPU-z and/or Sandra 2005 to verify the current multiplier and the voltage of your CPU.

Now go ahead and run Prime 95 on ‘Stress Testing’ mode for about 15-20 minutes to verify the short-term stability of your new setting. Keep lowering your voltage and going thru the above process until you get an error in Prime 95. Then go back and set a higher voltage and stress test it again.

Once you reach what you think is an optimal setting (no errors after 15-20 minutes) run Prime 95 for about 24 hours to make sure your computer will be 100% stable with the new setting. On my laptop, I was able to lower the voltage to 0.700v at 600 MHz. This is a reduction of 5.0 watts from the stock 8.0 watts to the optimized 3.0 watts in my case. This is a wattage reduction of almost 63%. Once you are sure that it is stable, write down the settings for future reference.

Now we need to go back to the settings for High, Middle and Minimum and make them permanent on the laptop. We need to verify that all the settings are correct in Crystal CPU ID and set the program so that it loads with Windows and automatically activates the multiplier/voltage management feature.

How To Auto Start Crystal CPU ID With Windows

Check in which directory the Crystal CPU ID executable file was installed by right clicking over the icon on your desktop. In my case, it was in ‘C:Program FilesCrystal CPU IDCrystalCPUID.exe’.

Now edit the ‘Target:’ value by adding ‘ /HIDE /CQ’ right after the original value (please note the spaces). Now when you right click on the shortcut the target box should read like this, ‘”C:Program FilesCrystal CPU IDCrystalCPUID.exe” /HIDE /CQ’.

Copy and paste this shortcut to the startup folder in the Start’Programs’Startup. This will enable the “Crystal ‘n Quiet” multiplier/voltage management to start when Windows loads.

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Figure 5: Placing Crystal CPU ID in the Startup folder.

Conclusion

Was it all worth it? Of course the answer is yes.

With a wattage reduction of about 63% at 600 MHz and 42% at 1.6 GHz, your battery life will be extended, your CPU cooling fan will be running less often (quieter), your laptop will feel a bit cooler and its life expectancy should be better. These voltage differentiations also hint to the high overclockability of the chips. These features will go far into enhancing your laptop computing experience everyday. Enjoy!

Richard Keeler

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