Windows XP Installation.

Once the BIOS was enabled, the next task was to obtain a driver. I downloaded that from the Athlon 64 downloads page. In my case I have plenty of bandwidth, so I downloaded the executable, but there is also a .zip file available. When the driver finished downloading, I just ran it. Once it started, it took over and completed the installation for me. A quick reboot, and it was ready... but not yet running.

Enabling Cool'n'Quiet is done via the desktop menu. Right click on the Desktop and select "Properties". When the properties page appears, select the "Screen Saver" tab and click on the "Power..." button to bring up the power control menu. Use the "Power Schemes" drop down list and select "Minimal Power Management". Hit the "Apply" button, and you're done.

Windows XP Observations.

All of this is great. We now have a system that saves power... or do we? It's kinda hard to tell by looking at the screen. I wouldn't recommend grabbing the heat sink in your hands to see if it runs cooler either. What I would recommend is using the AMD PowerNow Dashboard Demo. You can download it from the previously mentioned Athlon 64 downloads page. Unzip the package and run the resultant setup.exe program. Reboot if you are asked to.

Run the program and check out the graphical guages. If you are following along at home You should probably see the CPU voltage set at 1.100V, and the CPU frequency cut to 50% (1GHz in my case). If you don't see this, check your work so far. You should have the BIOS Cool'n'Quiet enabled, "Minimal Power Management" setting selected.

If you are set up right, you should also see the power savings meter is pegged at maximum. Pop open a browser, pop up the menus, do some stuff that taxes the CPU a bit and you will see the guages jump around and dance on cue. Try going back and temporarily set the power scheme back to home/office. The voltage and frequency guages should jump to maximum and stay there. Set it back to "Minimal Power Management", and watch the guages dance again. Neat stuff, Eh? But can it be independantly verified?

I was able to determine to my satisfaction that the PowerNow software was changing the voltage and frequency on the chip by using the MSI Core Center application that came with my motherboard. Core Center is usually used to set up overclocking and overvoltage parameters for the system while monitoring the temperature and fan speed for the system and the CPU. I focused on the CPU temperature and frequency monitoring it supplies.

As soon as I popped the window open, it was apparent that the CPU was running at reduced settings. The core voltage reading, which is usually at just under 1.5V, was now at 1.07V, close to the 1.100V claimed by the dashboard. The CPU frequency was set at 1000 MHz, though it is usually at 2000MHz. I went back and changed the power scheme back to my normal settings and watched the values jump back up to their normal numbers. This indicated to me that the AMD dashboard claims were correct within a small (estimated) margin of error. That gave me the confidence to continue on to a quick test of whether there was actually any less heat dissipated.

I let the system idle at these settings for a while. An unscientific while. probably about 10 minutes. I theorized that if the power dissipation were to drop, I would either see a noticeable drop in the CPU temperature or the speed of the CPU fan. After the unscientific settling period, I saw the CPU temperature drop from 35 degrees C. to 32 degrees C. The CPU fan speed dropped from 3125 RPM to 3068 RPM, but that is a single speed step, and it tended to oscillate between these two values.

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