I was able to compile the aqc111 driver thanks to the info here. If I do an "iperf3 -c XXX.XXX.XXX.XXX" transfer I get rates at about 2.75 Gbits/s transfer speed and it works reliably time after time. But when I transfer in the reverse direction, with iperf3 -c XXX.XXX.XXX.XXXX -R it initially...