NAS server - How slow can I go on my processor?

For close to the same price you can get the dual-core Celeron G530: http://www.superbiiz.com/query.php?categry=0&s=G530.

If you're doing something that low powered, you could probably get a whole PC off craigslist that would do the job.

I have no idea what your videos are saved at, but if plex needs to transcode you will want 2 cores, and some more beef in processor speed.

Why are you building rather than buying from a regular NAS maker? If you care about size, power, quietness, ease of setup, maintenance, cost, then go for one of those.
If you are determined to build yourself (e.g. to install whs, or if you enjoy customizing linux), try this efficient board from intel: DN2800MT

It kinda depends on what OS your gonna use and how your gonna config your disks.

I use a super micro atom processor board and it works fine streaming. I have 18 disks, 8 on a raid card, 4 on the board, and the rest n expanders. OS is win 2008.

Is at 60 watts at idle with the drives spun down. I don't transcode. It does however run all of my backups to the amazon cloud at night. Other than that it does nothing else but file serve. It was up for 410 days before I had to shut it off to physically move it. The one I have is probably 18 months old and I see no reason to upgrade it anytime soon.

For just NAS functionality (no transcoding etc), check out FreeNAS. Its a FreeBSD based OS build specifically for NAS functionality. Hardware requirements are very modest - see their wiki for more.

Just get something with a big case and dual core processor from craigslist ($100 max), beef up the RAM and possibly the NIC, maybe a SATA card and you're good to go.

Edit: there's a fairly good, recent intro article on FreeNAS at engadget...

Raspberry Pi is likely the lowest now. Still limited release ATM but there are some in the wild as they say. But it will run simple Linux (read: small) so things like FreeNAS shouldn't be a problem though somebody might have to write an update for the source code to support ARM processors.

The updated version for sale has two USB 2.0 ports and will support a powered USB Hub. A couple of externals + Raspberry Pi, hmmm sounds like a project...

I bought an off-lease (from a hospital) Dell GX-320 for $50 and used that as the base for my WHS 2011 build. I added 2GB of 800Mhz DDR2 for $30 and WHS 2011 for $50 from Amazon. I had previously bought a 2TB drive for $60AR so total investment to get up and running was $190. I then upgraded the network to 802.11n for another $60 (a series of price matches and discontinued product).

So not bad for $250 and it will stream 720p without a problem.

Anything Sandy Bridge will be many times faster than you will ever need for file serving.

For a point of comparison, my firm runs a 2TB NAS for filesharing duties among 20 people on a Pentium 4.