I know this is an old post but wanted to share my experience with this NAS.
I was getting slow transfer speeds of maximum 12MB/s with my original setup:
Pro Duo plug into my Router with 10/100 ethernet sockets
PC (gigbit card) plugged into Router
Cat 6 cable throughout.
Copying 12GB file from NAS to PC
My next setup which gave the same speed rates was:
Pro Duo plugged into a different router with 100/1000 (gigabit) ethernet sockets
PC (gigbit card) plugged into Router
Cat 6 cable throughout.
Copying 12GB file from NAS to PC
My next setup which works was:
Pro Duo plugged into gigabit switch
PC plugged into gigabit switch
Gigabit switch plugged into 100/1000 Router
Cat 6 cable throughout.
Copying 12GB file from NAS to PC
This setup gave me an average transfer rate 80MB/s. It topped out at 98MB/s and was no slower than 70MB/s Result!
So my assessment is that if you plug anything into the router the hardware of the router will throttle your transfer rates from the NAS - buy a gigabit switch and watch it fly!
Buffalo could be a bit more helpful on their packaging to say what setup they had to get their transfer rates - but then I suspect they are worried that they would be held accountable if users use different hardware to them and don't get the same results - maybe!
The switch I used is:
Netgear Prosafe 8-port Gigabit Desktop switch - GS108UK v3 - you can pick it up at PC World on special offer for £39.99 as of today.
I really hope this helps.