It’s been awhile after I posted the first blog on the subject (AMD-64 on Compact Presario R3000). I just want to update the status on this issue: I one day checked AMD website and found out an information about “Windows XP incorrectly reports CPU clock”. Overthere, they suggest users to upgrade the laptop BIOS. I followed their instructions and reboot my laptop.
Do you know what happened after my Windows XP rebooted? the CPU went to full clock speed and never scale back. The fan started to spin after a few seconds later and kept running. I checked CPU temperature (via 3rd party software I downloaded for free from the Net), it showed temp. close to 90 degrees Celsius! After a few minutes the computer turned off by itself (not a gracefuly shutdown!). I was like that no matter what I changed on the powersaving settings on Windows. Damn! (well, there was workaround. I used another software to manually control the CPU frequency back to 800 MHz to prevent it to overheat and shutdown). I checked on Microsoft site, the rebooting problem was caused by overheating.
I almost gave up (and did not use Windows during the time, but reboot to Linux partition. Linux successfuly control the acpi with no problem, besides it never reboots my computer). Finally, I give a try to download the latest AMD driver and reinstalled on my Windows. Somehow it now worked! (I am pretty sure I did exactly the same a few time before with no luck. So I believe there must be a fix in the newer driver).
Now PC is working OK. The frequency could scale up to its maximum (2.2 GHz). There is only 3 stages of frequencies: 800 MHz (base clock), 1.8 GHz and 2.2 GHz. The fan would turn on after a few seconds of CPU running at maximum clock and the temperature stabilizes around 80 degress Celsius, hence the Windows never reboots.