I've read that a lot and after trying a few NAS I dumped them and went back to a small PC for the NAS work.
Since it's all wired you can try one thing before you discover what I did. It helped so maybe these few tips can improve it enough for you to keep the NAS.
1. Turn off the WiFi radio in the router for a test.
2. Don't use the switched hub in the Super Hub. Get a normal switched hub.
3. You didn't write much about cables. If any are home made, tell me the wiring pair system you used.
I've seen folk debate item 2 but I can't debate it. I only share that it can help.
I am usually a fairly technical person, but when it comes to networks I am a total beginner.
I have internet through Virgin Media - about 60mbps. I have the Virgin Media Super Hub as my router.
I have connected a NAS, a Sonos Bridge (for my Sonos music streaming system) and PC directly to the ethernet ports on the router.
I have also connected the router to my plug socket using a home plug so that I can get wired connections anywhere in the house.
I have a Boxee (for streaming video to my TV) connected to a plug socket using a home plug so that can be on my network.
All of the above is in the same room (a relatively small room).
This seems to work fine a lot of the time. However quite regularly when I am streaming a video from my NAS to the Boxee it stutters, and then stops. I have read on Boxee forums that a lot of people have had issues in the past with this, however the issues I read about seemed fixed. Plus, if it was a Boxee problem then the rest of my network should be fine.
As a test, I streamed a music album from my NAS to the Sonos Bridge (each song was only roughly 7MB), which in turn used it's own network to stream to the Sonos speaker. At the same time I streamed a video (approx 350MB in size) from my NAS to the Boxee. Now this was working fine for a little while. But then all of a sudden the video clip stuttered and stopped, and at the same time the song playing on my Sonos stuttered and stopped.
So this to me proves something is amiss with my network rather than the Boxee.
The way I have this all setup, is it the best way? Everything is using ethernet ports, nothing is wireless. Is there a way to try and diagnose this?
And as I type this message, a song on my Sonos system stuttered for 20 seconds before starting again. This is with the Boxee turned off, so the Sonos was the only thing running.