From the network.png screendump I guess that you are using vSwitch1 to your NFS traffic?
What I see in the network.png screendump you are only getting 5 Mb throughput - And yes that is very slow!
There are no packet drops.
What do you see in VNXe Unispere in the performance graphs?
No other errors in Unisphere?
Last time I had slow data transfer too a VNXe (80Mbps) was because the SP B was failed and the write cache disabled..