Hi dualamd,
Please refer to Mellanox Technologies: VMware: Firmware - Driver Compatibility Matrix for the latest links for Firmware/Driver.
If you want to use your adapter as an Ethernet adapter, then the version you originally used is fine (1.6.1), any PSOD you get with this version should be reported to support@mellanox.com.
If you want to use the adapter as an InfiniBand adapter, then please use version 1.8.1 as yairi suggested (it's also listed i the matrix url above), the module responsible for showing the network adapters (to make use of vmnic uplink over InfiniBand fabric) is called ipoib, the user manual under Mellanox Products: Mellanox OFED Driver for VMware® ESXi Server has instructions on how to enable/use it. please also note you must have a functional InfiniBand fabric with Subnet Manager entity (more details in the user manual).