This article “Network File System ( NFS ) in High Performance Networks” by Carnegic Mellon is very interesting article about NFS Performance. Do take a look. Here is a summary of their fundings

1. For point-to-point throughput, IP over InfiniBand (Connected Mode) is comparable to a native InfiniBand.
2. When a disk is a bottleneck, NFS can benefit from neither IPoIB nor RMDA
3. When a disk is not a bottleneck, NFS benefits significantly from both IPoIB and RDMA. RDMA is better than IPoIB by ~20%
4. As the number of concurrent read operations increases, aggregate throughputs achieved for both IPoIB and RDMA significantly improve with no disadvantage for IPoIB