OK guys,
as found in the database x plane supports eyefinity, but do you really want that? Definitly not.
I started at 5040x1050 and if you play offline you will normally dont get in trouble. Setting this up with 130° FOV took about 3 Minutes.
So why would you not like to play at that resolution?
X Plane 10 comes with an openGL engine. Most parts of x plane are driven by cpu. When you start with x plane 10 default planes you will get about 40 to 50 fps, so everything fine. I love to fly by instrument flight rules, heavy aircrafts like Airbus 320 or Boing 777. First you need to pay for these excellent aircrafts, as they are 3rd party updates, and then you will see your fps dropping.
My Computer is watercooled, the cpu has been @ 3.5GHz, most graphic settings on medium to low with A320 i got 15-20fps. What a mess, can i see just one core at about 30% working and the R9 280X alone, because crossfire doesnt work, about 15%. So overclocking to 4.0 GHz gave me some extra fps, but with high detailed planes / cockpits you will have to lower the graphic too to get about 25-30 fps.
X Planes architecture is not to simulate (do not ever say "play" inside community, you will get killed) a whole cockpit with one computer, its designed to be used on a network of computers, and here i can tell the developers are clever. I see 80% of my hardware unused, having poor performance,
their design is one computer with one heavy cpu core, one monitor, and for every more display you can connect via LAN another computer with one high core clock, but then you need an extra licence for every x plane instance, and for every addon you bought.
The number of extra computers is not limited, within the display settings you can setup a offset, to put these extra monitors left, right, up, down of your main monitor.
So as result:
Eyefinity works, its easy to setup. some extra addon aircraft gets some trouble with overhead menus like the 777 wordliner, where the box of fuel, passenger and aircraft doors and extras is not optimized.
But show me one computer which is able to run x plane 10 with 4 displays, all settings to excellent eye candy, and having stable 30fps or more, which is needed that the game does not secretly change the simulation rate under 1.0.
On an online session an aircontroller whispered me why i would fly with 120 knots, while i disagreed, having 160 knots, and then whe found out by using the ingame cockpit stopwatch with a normal stopwatch, while ingame 5 minutes passed by, in real time it where 7, x plane tries to reach 30 fps, by setting the simulation rate less than 1.0.
So my conclusion, technically no problem with x plane and eyefinity, but gameplay will be a mess due to a poor hardware performance.