This paper presents an analysis of four runtime power management features implemented in AMD's recent 28nM APU. These features optimize SOC performance by shifting power and frequency resources in response to workload characteristics. The Global Efficient APM (GEAPM), Core-Bound Boost (CBB) and Memory-Bound Boost (MBB) features are shown to provide a performance improvement of up to 76%, 4.3% and 12.5% respectively. The Local Efficient APM (LEAPM) feature is shown to reduce average CPU power consumption by 34% while reducing performance by less than 1%.