Hi,
What is the specifications of the SFP+ MAC ?
The BPI-R3 MAC is fixed at 2.5Gbps allowing the PHY rate adjust to the cable link speed.
Is the BPI-R4 MAC fixed at 10Gbps or can its clock rate be varied, for example, so SFP transceivers that expect a MAC that can do 2.5Gbps can be plugged into the SFP+ slot and still work.