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I have a web server with CentOS 5.8. My hosting provider says that I have e6600 with 2.4GHZ.

I tried the following and I get different clock speeds each time. Is my CPU underclocked?

cat /proc/cpuinfo  | grep MHz
cpu MHz         : 2394.000
cpu MHz         : 1596.000

after a minute:
cat /proc/cpuinfo  | grep MHz
cpu MHz         : 1596.000
cpu MHz         : 1596.000

cat /proc/cpuinfo  | grep model
model           : 15
model name      : Genuine Intel(R) CPU                  @ 2.40GHz
model           : 15
model name      : Genuine Intel(R) CPU                  @ 2.40GHz
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1 Answer 1

up vote 1 down vote accepted

The speed reported in /proc/cpuinfo is the current speed of the processor. Intel processors include a technology called Speedstep. Speedstep dynamically adjusts the speed of the processor based on CPU utilization. It is fully supported in the Linux kernel since v2.6.

I suspect that you're simply looking at /proc/cpuinfo when there is little to no load on the processor.

Here is an interesting article that details some userland tools you can use to obtain more information on Speedstep in your system. One of which is cpufreq-info.

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Plus, unless that is a dedicated server the CPU speed is meaningless. –  John Gardeniers Oct 1 '12 at 21:02
    
Thanks! do you know if linux calculates server load (which can be seen in top, uptime, etc) according to the low clock speed or according to the max speed? –  Niros1 Oct 2 '12 at 16:51
    
The load, as you see in top and uptime, is independent of (but correlates with) Speedstep operation. The load, put simply, is the number of processes that were waiting for CPU time in the last minute, five minutes and fifteen minutes. en.wikipedia.org/wiki/Load_(computing). As your load gets higher, your P-states will change until you're operating at full speed. I will guarantee that at a load of 1 (not overloaded) or over 1 your processor is operating at full speed. –  Sean C. Oct 2 '12 at 17:06
    
Load == CPU queue length; Speedstep P-States correlate to CPU utilization. They are different concepts, but one affects the other. –  Sean C. Oct 2 '12 at 17:08

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