Apparatus and method for managing power consumption of circuits within a Serial Attached SCSI (SAS) device. A SAS device having a plurality of PHY logic circuits includes a queue manager and a power manager. The queue manager is operable to determine a current workload based on queued entries for the plurality of PHY logic circuits. Based on the current workload, the power manager is operable to set identified ones of the plurality of PHY logic circuits into a low power mode. In some embodiments, PHY logic circuits may be restored to full power operation responsive to changes in the current workload and/or responsive to receipt of a signal from another SAS device coupled to the SAS device. In other embodiments the power manager is further operable to manage power consumption of link and/or DMA logic circuits of the SAS device.