A measure of how fast a given system might be. It is calculated by taking the elapsed time that was measured for a system to complete a specified job and dividing that into the reference time (the elapsed time that job took on a standardized reference machine). This measures how quickly, or more specifically, how many times faster than a particular reference machine, one system can perform a specified task. SPECratios are one style of metric from the SPEC CPU benchmarks, the other are SPECrates