different display quality with same lcd's in synchro

Hi,

I'm coming to you because there is a problem i can't resolve.
I got 9 brightsigns hd210 and 9 Samsung 460-ux3 LCD screens. (linked with hdmi)
I m used to play a big video on it using a dlink switch and LAN cables.
The problem is that it always suffers of one or two screens displaying not as good as the others.

On these ones, the picture :
- has more pastel colors
- doesn't feed exactly the entire screen (and so is not well alignated with the other parts of the video)
- vibrate a little bit

As i launch simultanously the whole system, all the screens turn on. Good screens become a little bit less dark, recieving the brightsigns signals, waiting for media and i can already see that the screen(s) going to be bad, are more luminosous, like à bad grey.

Some points :
- the problem is not attached to one or two of the screen i got, if i stop the system, invert 2 screens and relaunch, the problem stays at the position it was, not on the screen. (this point let me think it comes from the streaming system)
- i got one or two bad pictures for a 9 screens installation, and zéro or one bad picture for a 3 screens installation. So i never succeed to install 9 screens without this problem.
- one of the most strange thing : if i launch the osd of a screen presenting a bad picture, the menu is different than the others one. For instance, in picture settings preset, i will have the choice between "promotion", "entertainment" or "cinema" where the others propose "dynamic","normal", "movie" (i m not exactly sure of the words). If i remove this screen from the sync. 9 scr. Install. and i just connect to it one brightsign, picture and osd become ok.

As I powered on all simultanously, I was thinking first some screens didn't have the time to start properly. So i got now a system to launch first the screens and brightsigns + switch are powered 2 minutes later. Unfortunately, it didn't resolve the problem.

So, if you have found the patience to read, perhaps you could give me some ideas !?