[SOLVED] Why do my cpu cores have different speeds?

I have an Intel 4-core processor. When I look at /proc/cpuinfo, the cores all seem to be running at different speeds. Core 1 is the fastest at 2372 MHz, cores 2 and 4 run at 1332 MHz, and core 3 a little faster at 1416 MHz.

Why does this happen and is it normal:scratch:?