On Friday 13 April 2007, Mark Hull-Richter wrote:
> I know this is a bit OT, but the subject of CPU speed came up here and I
> was (and have been for some time) curious:
>
> What is the actual speed of an AMD CPU? E.g., I have a Athlon 64 X2
> "4200+" but my /proc/cpuinfo shows 1005.164 MHz for the two cores.
>
> What do those mean? Is there a reference for this (huge) discrepancy?
>
> Also, is there a way (and what) to tell what the actuall running speed of
> memory is?
>
> Thanks.
4200 is a performance rating... Originally they modeled after a Pentium III,
later switched to comparing to Duron performance. With dual core everything
got even harder to determine - but important thing is that 4200 is just a
relative rating and doesn't mean 4.2Ghz.
The 4200+ is a 2.2 Ghz processor. That means it will run at a maximum of
2.2Ghz. Power needed by a CPU is determined by clock speed. So to preserve
power, the CPU can clock down. How far and how many steps depends on the
specific CPU and board/bios. It seems that your box is fairly idle and the
CPU was clocked down to 1Ghz to preserve power.
Look in /sys/devices/system/cpu/cpu0/cpufreq. There you will find several
files. cpuinfo_cur_freq contains the current CPU frequency and should be the
same as you get from /proc/cpuinfo. scaling_available_frequencies are the
different frequencies that your kernel/cpu/bios support.
You can try it out easily - do something very cpu intensive and then check
again, your cpu frequency should have gone up to 2.2Ghz.
Peter.
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