Dmesg and cpuinfo MHz differencies

I can see different values of CPU MHz here:

cat /proc/cpuinfo

model name : Intel(R) Xeon(R) CPU
E3110 @ 3.00GHz stepping : 6
cpu MHz : 2000.000

Model say 3GHz and cpu MHz say 2GHz but

dmesg | grep MHz

say

CPU0: Intel(R) Xeon(R) CPU
E3110 @ 3.00GHz stepping 06 CPU1:
Intel(R) Xeon(R) CPU E3110
@ 3.00GHz stepping 06

Why there is 2GHz shown?

Your CPU and operating system are utilising Intel’s SpeedStep technology. This allows the CPU to dynamically vary it’s clock speed depending on load, etc.

The 3GHz you see is the maximum that your CPU is capable of and the 2GHz amount is what it is currently running at.

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