CPU-Z is a freeware that gathers information on some of the main devices of your system. 

Name and number.
Core stepping and process.
Core voltage.
Internal and external clocks, clock multiplier.
Supported instruction sets.
Cache information.

Vendor, model and revision.
BIOS model and date.
Chipset (northbridge and southbridge) and sensor.
Graphic interface.

Frequency and timings.
Module(s) specification using SPD (Serial Presence Detect) : vendor, serial number, timings table.

Special Keys :
F5=> key allows to save a screenshot as a bmp file in the application directory. These are named cpu.bmp, cache.bmp, mainboard.bmp and memory.bmp.
F6=> key copies the current page in the clipboard.
F7=> key saves the validation cvf file in the current directory.
F9=> key switches between CPU clock computation methods.