Radhead:  I started with the analog version and moved on to the digital version, and although undoubtedly there is a performance hit, it improves the sim experience to such an extent that I could never go back to a single screen.

It seems to me your problem might just be that the presentation is zoomed in on start up.  Try the (-)key to see if it will zoom out.  FSX is a curious beast, you only have to start up once like that and it will remember it forever.

Also hit Alt+Enter and bring the whole presentation down to a small window, test the zoom, get it right and go back to Full Screen which will spread it across the three screens again.  Usually I find any functional hiccup sorts itself out through that process.

If that fails your screen may be set to a different resolution than the 3840x1024x764 of the game.  Check to make sure that they are the same.   Right click on an empty space on a screen, find NVidia Control Panel on the menu, click that and then click on Multiple Screen  (something, I'm away from my computer so its from memory).  Make sure the resolution is set the same as the in-game setting (on the graphics screen) of the Settings menu.  The one we all fiddle with continuously.

Also check in the fsx.cfg that widescreen is ...=False.

There is also an nHancer and a 3D setting thru control panel again that ensures the game knows that you are in multi-screen mode. (although this is probably unnecessary for three screens, because Matrox tells the card to treat it as a single screen).  I use a fourth screen from the other outlet of the vidcard to park GPS, ATC and the like on.

I use a yoke and I have one of the left/right switches set up for zoom so that I can bring instruments right up to me if I need, then push back out again.  Also if your game is stuttering, especially in Spot view you can also zoom in, about half way, and although the resolution is nowhere as good, it reduces the load on the CPU and the vidcard.

if this is a little vague, because I am not in front of my computer please PM me, but I have had no trouble setting FSX up on matrox TH2G.