The core-C6 (CC6) sleep state of the AMD bobcat x86 microprocessor

This paper describes the architecture and physical design of the AMD Bobcat x86 microprocessor core-C6 (CC6) sleep state. Each core and dedicated 512KB L2 cache use control flows to save and restore the x86 architectural state in concert with a network of PFET sleep transistors that drive an internal voltage domain. Measured results show an approximate 92% reduction in leakage power at the cost of 1-3% die area with a 31μs restore latency. Each core and L2 cache pair use 98cm of total sleep transistor width in a TSMC 40nm bulk CMOS process.