CPU-Z

From CPUID:CPU-Z gives you information such as processor name and vendor, core stepping and process, processor package, internal and external clocks, clock multiplier, partial overclock detection, and processor features including supported instructions sets. This program supports detection of the processor’s core voltage, L2 bus width, support for two processors (in Windows NT or 2000 only), and memory timing (CAS Latency, RAS to CAS, RAS Precharge).