9 MB/s in ReadyNAS NV+ v2 with RAID5

I am having a similar experience with poor performance against benchmark figures for my Netgear NV+ v2. My speeds are around 29MB/s write and 23MB/s read (yes write is faster than read). Connected via a Netgear GS506 GB switch with cat6 cable. If I restart the NAS I can get close to benchmark speeds but shortly after reverts to the speeds quoted above. These are via SMB shares. Another test I do is with my Netgear NeoTV550. The network test shows 60+Mb/s from my ReadyNAS Duo V1 but only 19Mb/s from my ReadyNAS NV+ v2. I only use these two devices to share my movie collection with 2 550's. These speeds from the NV+ are not fast enough for Blur-ray ISO's. I have noticed one share that I created (nothing to do with streaming) has no sharing protocol checkmarked and errors when you try to select SMB?? Certainly I will create another share and move my data across. I bought this for some extra space and expectation that it would also out perform my Duo V1 but it is struggling to do so. Running the latest firmware. Any ideas on how to get this to work closer to benchmark speeds would be appreciated?