confuse about CPU's information

Jake L

Honorable
Feb 3, 2014
20
0
10,510
I've bought a core i5 2500, then I right mouse to the computer icon and look for the information in "properties", It say " Intel(R) Core(TM) i5-2500 CPU @ 3.30GHz 5.90GHz"
what's the "5.90ghz"..I dont understand..please help..