Route based on source MAC hash

This principle is the same as the default policy but is based on the number of MAC addresses. This policy may put those VM vNICs on the same physical uplink depending on how the MAC hash is resolved.

For MAC hash, VMware has a different way of assigning ports. It's not based on the dynamically changing port (after a power off and power on, the VM usually gets a different vSwitch port assigned) but is based on fixed MAC address instead. As a result, one VM is always assigned to the same physical NIC unless the configuration is not changed. With the port ID, the VM could get different pNICs after a reboot or VMotion.

If you have two ESXi Servers with the same configuration, the VM will stay on the same pNIC number even after a vMotion. But again, one pNIC may be congested while others are bored. So there is no real load balancing.