Code taken from http://www.808.dk/?code-csharp-nas-performance
Basic bugs fixed (threading) + 4.5 .NET support + very basic cleanup
This free utility benchmarks the read and write performance in megabytes per second of network attached storage connected through SMB/CIFS network shares.
NAS performance tester 1.7
How it works: Temporary files of arbitrary sizes are generated and copied to and from the NAS a number of times, whereafter the average read and write speeds are calculated.