CPU Burn-in's the ultimate stability testing tool for overclockers.
The program heats up any x86 CPU to the maximum possible operating temperature that is achievable by using ordinary software. This allows the user to adjust the CPU speed up to the practical maximum while still being sure that stability is achieved even under the most stressful conditions.
CPU Burn-in continuously inspects for calculating errors ensuring the CPU does not generate fatal errors during calculations during overclocking conditions.

The license of this software is Freeware, you can free download and free use this cpu benchmark software.