# [SOLVED] Wrong Processor Speed (AMD Mobile Sempron)

## Boesmann

I have a somewhat strange problem...

I bought a new laptop in December, Processor is a Mobile Sempron 2800+.

I made a networkless install (Gentoo2006.0 LiveCD), afterwards I compiled a new kernel (Gentoo-sources, 2.6.16) with the recommended safe C-flags (march=athlon-xp -O2 -pipe).

So far so good, everything works just fine.

Now I wanted to install some power-saving features (frequency scaling, ...) and I noticed that /proc/cpuinfo reports my processor to be:

```
...

model name: AMD Mobile Sempron(tm) 2800+

...

cpu MHz : 799

...

bogomips: 1599.84

```

MHz and bogomips seem to be quite consistent; anyway the processor should be running at 1600 MHz!!!

I had the same problem with WinXP (which was, of course, pre-installed on the system), but the AMD support assured me that this is an XP display error, and, right enough, the AMD cpu-info tool showed 1600 MHz.

So now I'm really confused   :Confused: .....

Did they rip me off? (...I don't think so)

Is this a kernel problem?

Could it be BIOS related?

Did I do somehting wrong? (...most probably)

Any advice or hints would be greatly appreciated!!!Last edited by Boesmann on Fri May 12, 2006 3:55 am; edited 1 time in total

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## mbar

Some BIOSes initialize mobile CPU to lowest powersaving state, e.g. lowest frequency. This is not correct with AMD guidelines that state mobile CPU should be booted with highest performance state (highest frequency), and powersaving should be started when OS is fully loaded.

You can try and find BIOS update or simply emerge cpufrequtils and configure ondemand or conservative governor (from my experience with athlons xp conservative works better) which will scale up frequency when CPU load increases. Remember to configure kernel also...

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## Boesmann

Great news!

Thanks for your reply, I will give it a try tomorrow!!

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## olger901

1 Make sure that AMD Powernow is compiled in your kernel 2 Afterwards run modprobe powernow-k7 (in case of an Socket A proc) or modprobe powernow-k8 (incase of a S754/S939 proc) and it will run at full speed.

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## Boesmann

 *olger901 wrote:*   

> ...modprobe powernow-k7 (in case of an Socket A proc) or modprobe powernow-k8 (incase of a S754/S939 proc)...

 

Any recommendations on how to determine this?

I already tried, but there seems to be a lot of confusion regarding this topic. Ask 3 people and hear 3 different versions   :Rolling Eyes: 

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## Boesmann

Thank you very much, activating PowerNow has solved my problem!

And if anyone wants to now: all Mobile Semprons are Socket 754.

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