Intel® Core™ i5-2450M Processor (3M Cache, up to 3.10 GHz) the 3.1 GHz clockrate is 'up to', not continuous. After the work is done, it will go back to 2.5 GHz. That means when one core of your cpu is working, the cpu will auto overclock the core to 3.1 GHz as long as thermal headroom is available. The cpu has base clockrate of 2.5 GHz and turbo 3.
