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I ran this command on ssh to see CPU info: cat /proc/cpuinfo And it says:

...
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping        : 3
cpu MHz         : 1400.000
cache size      : 2048 KB
...

Why is cpu Mhz 1400 ? Wasn't it supposed to say 3000Mhz ? OS is CentOS 6.0

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the 1400 means that at which speed the processor is running RIGHT now. 3000 is the Max cpu speed.

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    +1 This. And the reason is cpu throttling, which makes you have a smaller electricity bill and helps saving penguins. It's a feature that "scales down" the speed at which the CPU completes operational cycles (1.4 billions per second rather than 3 billions) and that uses less power. The cpu is smart enough to "gear up" everytime you need more calculation power, shifting back to 3 Ghz.
    – ItsGC
    Commented Nov 12, 2011 at 14:11
  • Yes, I just found out now that there is a service that can be started/stopped, I let it on. Interesting.
    – adrianTNT
    Commented Nov 12, 2011 at 14:53
  • ...and the most interesting part is that almost every CPU nowadays will throttle down, since the CPU-speed is normally never the bottleneck.
    – Nils
    Commented Nov 12, 2011 at 21:41
  • Got the answer for what i am exactly looking for. Thanks guys.
    – 夏期劇場
    Commented Oct 9, 2013 at 6:06
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This is due to a service enabled in Linux. Its is a service called "cpuspeed".

If this service is enabled it will decrease the clock speed as the temperature rises on the processors.

Hence you just need to stop this service in order to get the max clock speed. By default this service will be off on Linux.

/etc/init.d/cpuspeed stop

Also make sure you switch this service off on boot.

chkconfig cpuspeed off

After this check the cpuinfo and you will find CPU MHz will be 3.00Ghz

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