help indentifying chips

does anyone know of resources where i can look up and identify cpu's based on the numbers on the chip itself. i have been scaveging used computers and removing various cpu's. most of these computers are incomplete and a pain to get functioning in order to use software to identify the cpu's. for example i found a an old pentium and would like to be able to identify the speed without rebuilding the computer it came in. thanks.

Sure, go to the Intel website and look up the s-spec.