Mellanox was bought by nVidia 2 years ago, so while it's technically accurate to say it's an nVidia card, that elides their history. Mellanox has been selling networking cards to the supercomputing market since 1999. Netflix absolutely had to do some tuning of various counters/queues/other settings in order to optimize for their workload and get the level of performance they're reporting here, but Mellanox sells NICs with firmware/drivers that work out-of-the-box.