POWER8 systems introduced a feature to keep it running under power and thermal limits. This improves
performance and energy management, while providing additional system reliability and availability.

A.
PowerVP

B.
Intelligent Power Distribution Unit (iPDU)

C.
Power-Optimized Cores

D.
On Chip Controller (OCC)

Explanation:
https://www.ibm.com/developerworks/community/wikis/home?lang=en_gb#!/wiki/Power%
20Systems/page/Overview%20of%20the%20OCC%20for%20POWER8