I have a similar problem: i cant get IP over IB working.
MT 27500 ConnectX-3 (PSID MT_1100120019) on ESX 6 (latest Updates 2 days ago). In the BIOS (SuperMicro) I set in the PCIe Configuration Page “Above 4G Decoding” as “Disabled” since otherwise the card was not recognized in older SuperMicro hardware.
First installed the 3.15.5.5 and also updated the firmware to 5150
Then had a vmnic2 with up to 40000, but link was down.
Then I uninstalled and installed OFED 2.4.0.0
Then had a vmnic2 with up to 1000GB, link down.
I also tried to install both drivers, same issue: link down, card is recognized as Ethernet and not IPoIB.
I already opened a support ticket with VMWare but the technician had no solution.
It seems the last know driver to work is 1.8.2.4 (see here VSphere 6.0 ) but this driver is not supported in 6.x
By the way: when you select now OFED 2.4.0.0. you are redirected to 2.3.3.1 for download (http://www.mellanox.com/page/products_dyn?product_family=36&mtag=vmware_drivers )
I had no problem with the same cards in similar (older) hardware and ESX 5.5.