Out of interest, what hardware is behind that setup on both ends (disk spec/ raid or not etc) ?.
If I have been running a machine on torrent duty for a few days then my transfers slow to around 50-60MB/s. Once the switch is reset then they raise to 70-80MB/s. The switch is a midrange (G-series) Netgear switch. I believe most home switches will have the same issues. Hopefully my HP Procurve 1810 will have a big enough address space to avoid this issue although my new network plan is routing the torrent box away from the main switch for a direct internet route.
RB
iperf (the tool I was using to test network bandwidth) doesn't involve the Hard Disk or any particular file sharing protocol when benchmarking, It's purely for testing your network setup.
My Windows File Transfers (2* SSD's RAID0 -> 8* Samsung F1 Hardware RAID5) Do reflect my iperf findings, I get just under 100MB/s. on large transfers.