The stock driver worked for me after upgrade from 6.5 to 6.7
You can even install the original Mellanox driver for 6.5, works as well.
Be prepared for problems though:
The Mellanox ConnectX-4/ConnectX-5 native ESXi driver might exhibit performance degradation when its Default Queue Receive Side Scaling (DRSS) feature is turned on
Receive Side Scaling (RSS) technology distributes incoming network traffic across several hardware-based receive queues, allowing inbound traffic to be processed by multiple CPUs. In Default Queue Receive Side Scaling (DRSS) mode, the entire device is in RSS mode. The driver presents a single logical queue to OS and is backed by several hardware queues.
The native nmlx5_core driver for the Mellanox ConnectX-4 and ConnectX-5 adapter cards enables the DRSS functionality by default. While DRSS helps to improve performance for many workloads, it could lead to possible performance degradation with certain multi-VM and multi-vCPU workloads.
Workaround: If significant performance degradation is observed, you can disable the DRSS functionality.
- Run the esxcli system module parameters set -m nmlx5_core -p DRSS=0 RSS=0 command.
- Reboot the host.
This is from the GA 6.7 release notes and i can tell you in Real life i have problems using storage vmotion since that problem under 6.7 makes my network speed go down to 5-10 mbits/s instead of 3Gbit/s.
Moving around VMs in 6.5 works fast. I would say wait for a patch or use 6.5 