Picked up a handful of old 10g mellanox cards and just direct connected my computers since even the used 10g switches are still expensive... i can reach double my 1g ethernet speeds but not near the 10g max. I'm thinking the pciv1 slots str holding them back...
Nah, 4x gen1 is sufficient, and your cards are surely 8x or 16x. use iperf for a reliable measure.