CPU Stability Test allows you to torture test your computer's Central Processing Unit (CPU) and find out if it is overclocked.
CPU Stability Test tests: CPU, Harddisks, RAM, caches and many sections of your Motherboard.

The program supports multi-processor systems, features automated crash handling and counting, includes stability rating, and lets you disable the screen saver.

Features:

Multi threaded
Supports multi-processor systems
Error (and CRC) checking
Supports MMX