Hello Matthew,
Trying running "ib_write_bw" again but specify the ib-device and "rdma_cm". Also, you can you use flag "--report_gbits"
Please see example below.
# ibdev2netdev
mlx4_0 port 1 ==> ib0 (Up)
Server: # ib_write_bw -d mlx4_0 -R --report_bits
Client: # ib_write_bw -d mlx4_0 1.1.1.109 -R --report_gbits
Cheers,
~Rage