So LID 1 is other switch. So this also a is false warning from that script.
ibnetdiscover says 4xQDR for all your links so this looks right. That would be 10 Gbps (signaling rate) derated to 8 Gbps (max data rate). What app are you running to determine 2Gbps thruput ? Switch/fabric looks OK to me unless there are errors being encountered. Try ibqueryerrors and see what it says.
