CPU-Z is a freeware utility that provides some information on your CPU :


Processor name and vendor

Core stepping and process

Processor package

Processor current core voltage

Internal and external clocks, clock multiplier

Partial overclock detection

Processor features, including supported instructions sets.

L1 and L2 cache informations : location, size, speed, technology.

Motherboard informations : BIOS, chipset, memory, AGP.
More info:
hxxp://www.cpuid.com/