cpu MHz

I have a quad-core 2.6 GHz processor. However, /proc/cpuinfo shows my speed as 1300 Mhz for all 4 cores. Does anybody know what might cause this. My BIOS properly reports my speed at 2.6Ghz.

Thanks,

Dave

What processor and linux distribution do you have?

AMD Phenom 9950 Agena 2.6GHz 4 x 512KB L2 Cache 2MB L3 Cache Socket AM2+ 125W Quad-Core Black Edition Processor - Retail

Ubuntu 9.04 (Desktop edition)

Did you get the 32-bit or 64-bit version of ubuntu, im not sure but that my be your problem if you got the 32-bit version.

I would expect this is due to cpufreq - CPU speed is scaled according to processor load.

You can Google for plenty of info.

Post the output of uname -a command here.

Code:

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uname -a

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You might have cpufreq scaling enabled (cpuspeed)

Take a look in /sys/devices/system/cpu/cpu0/cpufreq (in fedora anyway)

What you are intrested in is :

scaling_available_frequencies
scaling_available_governors
scaling_cur_freq
scaling_governor

On mine I get:

scaling_available_frequencies = 1900000 1800000 1000000
scaling_available_governors = ondemand userspace performance
scaling_cur_freq = 1000000
scaling_governor = ondemand

You change scaling_governor to performance by

echo "performance" > scaling_governor

This should make the cpu run st max speed.

Thank you blinky. That was just what I needed.

Why would you want the cpu to always run at the max speed? It's an useless waste of energy if the cpu is completely iddle.

I don't know. I probably don't need to. The reason I was looking to speed it up was I assumed it was running at that speed all the time.

How quickly will it increase to its full value if processesing power is needed?