for AMD peopleEdit/Update:
apparently with the newest processor drivers (i.e. 1.3.1 -- released in May 2006), the Power Management Tab will no longer appear in Device Manager windows. I assume this means that the new drivers do not support PowerNow!, or at least do not let you micro-manage the settings. If/when I find more information on the newest drivers & their power management capabilities, I will come back & edit this post again. The 188.8.131.52 drivers are no longer on AMD's website.***Original Post Follows***
For those with AMD processors, some extra degree of power management is available by downloading the latest processor drivers from the AMD website (links provided below). Oftentimes (as was the case with mine), the new laptop will have the WinXP processor driver installed--which doesn't have PowerNow! support, or at least, doesn't allow you to micro-manage the PowerNow! settings.
PowerNow! allows automatic powering-down of devices not in use (so you don't have to manually enable/disable them thru the Control Panel as recommended in the article above, unless you want to, but the effect is [pretty much] the same). Supposedly it also helps with processor throttling. Unfortunately, it works partly thru XP's Power Management window, so it doesn't bypass OS control of power management, but augments it. I recommend it, though, to anyone with a Mobile AMD Athlon64.
Once installed, you can go to the Control Panel--> Device Manager & open the Properties window for the devices you want to micro-manage. In the Properties window, you will now have a "Power Management" tab for certain devices (including USB hubs, PCMCIA card slots, WiFi, etc.). The default setting is to power-off each device when not in use (there is a check-box at the bottom of the Power Management tab in the window, which you can check or un-check).
Example: Since I never use my PCMCIA slot, I manually disable it (you can see that in the first screenshot), rather than let PowerNow! choose when to turn it off. But I _occasionally_ use my Ethernet port so I let PowerNow! automatically manage that by right-clicking on the Ethernet controller in the Device Manager, then clicking on the Power Management tab, & checking the box that says "Allow the computer to turn off this device to save power."
To install the new processor driver, simply download the .exe file & run it. I think the .exe file might be the same for all processors, but I'm not sure, so, to be safe, I'll give separate links for each processor. Somewhere in those pages you can also find a 'Cool & Quiet' driver for Linux, as well, but only for desktop systems; I don't think it works for Mobile chips yet.
Links (scroll part-way down & find Processor Driver 184.108.40.206 or 220.127.116.11 [18.104.22.168 is for 32-bit WinXP, 22.214.171.124 is for 64-bit WinXP]):Mobile AMD Athlon64Mobile AMD Sempron (32-bit)Opteron 64(non-mobile) Athlon64AMD Turion 64Dual Core Athlon 64Note:
once installed, the WinXP (32-bit) Device Manager will say that the Processor Driver revision is 126.96.36.199, but in fact it is the updated 188.8.131.52 [don't be put off by it]. Bon Apetit!~