Resonant clock design for a power-efficient high-volume x86-64 microprocessor

AMD's 4+ GHz x86-64 core codenamed "Piledriver" employs resonant clocking to reduce clock distribution power up to 24% while maintaining a low clock-skew target. To support testability and robust operation at the wide range of operating frequencies required of a commercial processor, the clock system operates in two modes: direct-drive (cclk) and resonant (rclk). Leveraging favorable factors such as the availability of two thick top-level metals, high operating frequency, clock-load density, and the existing clock-design methodology, the rclk mode was designed to enable both reduced average power dissipation and improved peak-power-constrained performance, with minimal area impact. This work represents a volume production-enabled implementation of resonant clock technology, and is plan of record for mid-2012 product offerings.