Methods and structures within a SAS domain for automated tuning performance of a coupled pair of transceivers. In one aspect hereof, control registers of a transmitting transceiver coupled to a receiving transceiver are adjusted to a plurality of distinct combinations of settings. For each distinct setting, a test pattern may be transmitted from the transmitting transceiver to the receiving transceiver. Status registers of the transmitting transceiver and of the receiving transceiver may be read to identify errors in the transmission. Identified errors are counted for each for distinct setting of the control registers to determine a preferred setting to best tune operation of the transceiver pair. The testing may be performed by any SAS initiator device or SAS expander acting as an initiator and may be performed on any coupled pair of transceiver in the SAS domain.