Thank you for your answer, that video is being run on an Ubuntu 9.04 machine, can you do the same on Windows?
can I just plug as many monitors as I want and arrange them with windows?
what happens if I run an app in full screen??
Do I have to do some config with softTH
I'm planning on using Matrox solutions as a last resource since they are way more expensive
I haven't done huge screen arrays in Windows 7 . . . but I'm not sure you can make a desktop that wide (1366 * 9). Though the 3x3 display should be fine.
Are you running DirectX games as one huge screen? If not then you don't really need SoftTH that I'm aware of. SoftTH just takes a game and renders it at huge resolutions on one video card and then sends it as images to the other monitors . . . So if you don't plan on stretching one game out over all the monitors I don't think you would need it.
If you are just playing videos, any reason it can't be on a linux machine like Ubuntu?
Also keep in mind that running 18 different video streams off of one storage system you may run in to bandwidth limitations there. Especially if you are using spinning disks since seek times will really eat in to your performance, since the videos will be running as if it's doing random reads.
If you take a look at http://www.anandtech.com/show/2738/25 you will notice in random read tests the spinning disks get around 1MiB/s. Though yours will be far better I'm sure because the data won't be anywhere near as spread out, but if your steaming 6Mbps 720P video to 18 screens you need to sustain at least 13.2MiB/s. It might be best to put your currently active videos on an SSD and only have a spinning disk for storage. If not that you could also run some benchmark tests on random reads of a 10-20GiB area of your drive you plan to use and see how it comes out.
If you like Matrox, I'm not sure if you can just get a couple of video cards and put Triple-Head 2Go's on all the outputs to make a huge display. It seems like they have some limitations in place . . . They do have products taht can drive pils of displays though: http://www.matrox.com/graphics/en/solutions/video_displ...
If you are really just streaming video you could set up a little NAS and hook each display up to a Raspberry Pi . . . Though you'd have to be able to control them all . . . it would be an interesting project.