RN102 Expected Performance?

I purchased an RN102 a few weeks ago and have just gotten it around to setting it up. It was the preconfigured model with 4TB (2x2TB Toshiba Drives).

Reading the report at smallnetbuilder, it looks like in RAID1 they were achieving 49.1MB/s write and 83.3MB/s read. I can't even come close to that. I assume that was with NFS, but both my NFS and SMB test are about equal. From a Windows 2012 (or Win 2008 R2) server (which is a guest in ESX) I can only seem to get about 45.5 write (not terrible!) but my reads are only about 52-53MB/s. The reads seem to fluctuate like crazy though, sometimes the reads will only be in the mid 30's range.

Am I dreaming of 49.1/83.3 with this unit? My writes using standard windows file copy are usually only in the 35 range, robocopy seems the slowest to NFS. I am able to get a test file of 1024MB sent to the NAS in about 22-24 seconds.

Any thoughts? RN is using 6.1.4, NFS 32kb with 8 threads (all default). Windows 2012 which seems to perform a little better uses an rsize of 64kb it seems, while 2008 use 32kb.

I have both systems connected to a dedicated 1gb unmanaged switch which has a single port uplink to the rest of the network. I want to get the performance sorted before I copy over everything from ESX to the NAS.