Sorry for no answers - thought the question was ignored and lost the link .
The model of the Intel IB-cards is AXX1FDRIBIOM as i've researched. As an update - the NFSoRDMA hangs not only with Win VMs, but just any VMs with no way to predict - there may be 100s of errors Connection closed error -103, and all is fine, or 1-2 lines and hanged up connection...