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Tuesday, December 19th 2006, 7:56am

Great bug with Cpu_scaling and OC'ed processors


I have an AMD Athlon64 3000+ running on 2.4Ghz for 2 years now (normally it runs on 1.8Ghz).

In windows , Cool&Quiet didn't have problems with that and adjusted the low and high speed for cpu scaling.

In Linux (every distro), the cpu scaling functions doesn't work correctly.
It seems that it looks for information about the cpu in the CPUID or something instead of looking on what speed it is really running.

My PC was running on 2400mhz and when Linux was booted, it went down to 1.8ghz maximum (on performance mode) and cpuinfo showed 1800mhz instead of 2400mhz.
People didn't know what the problem was and told me to try recompile the kernel with fake cpu settings etc etc.

I just disabled cool&quiet in the bios and suddenly linux was running full speed.(because cpu_scaling was not working anymore) and cpuinfo shows 2400mhz cpu now.

So it's a bug in cpu_scaling software. (in windows , the cool&quiet function correctly adjust the min and max speeds when you overclock your processor so it looks at the running speed and not at the cpu type)

I can understand that overclocking is not supported by anyone but the funny part is that the original cool&quiet drivers from AMD in windows does adjust the right speed when enabled.

So maybe you can't call it a bug because cpu scaling does what's expected, but it misses the feature to work at higher speeds then factory defaults ;)


This post has been edited 5 times, last edit by "AmpLiF1eR" (Dec 19th 2006, 9:48am)



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Location: Eindhoven

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Tuesday, December 19th 2006, 3:34pm

RE: Great bug with Cpu_scaling and OC'ed processors

So? It's not really KDE related you know.
Bram Schoenmakers
KDE Netherlands (