I have no idea how eyefinity works. I use an Nvidia card...always have. Anyways...
Left to itself with my vid card hooked to both the Dell monitor and the LG Tv, and just having the Dell monitor check marked...the Nvidia vid card will auto assign the LG TV as primary monitor because it is hooked up with HDMI.
The Dell is hooked up with DVI cable.
Like I said before, up until the GTX 680 it didn't matter, but the Nvidia cards after that (Titan and 780 Ti in my case) automatically set the primary display to whatever device was hooked up to the HDMI cable.
When I swapped cards from the GTX 680 to the Titan, I lost the Dell display (the TV was off at the time).
I called EVGA and said wtf? They said turn on the TV. So I did, and there was my desktop. So I had to use the mouse on the TV to open Nvidia Control Panel, and right click the #2 display (the Dell) and choose: Make Primary
I may have had to reboot, don't remember. But the desktop then showed up on the Dell, with or w/o the TV being on.
The point is...you need to check which display is set to be the Primary display. If it's not the one you want to have the desktop when you boot the computer, then you need to change it.
