We're sorry you are having issues with your Xfire. did you mean, "The game did actually run perfect with(OUT) xfire once it finally loaded"?
It does sound like a driver issue, but id be surprised if the drivers themselves were written wrong. Are you using the newest beta drivers? 15.11?
Tutorial for proper driver installation.
1-Load windows with only your primary graphics card plugged in.
2-Disable any and ALL anti-virus/malware protection.
3-Download and Run the 15.11 (or latest) drivers from AMD.com (Omega drivers do not have Uninstall built in, you have to do it through add/remove, which is okay)
4-Choose to Uninstall/express (may not be available in newest version, download an older version) the existing drivers, and AMD folder
5-Restart the computer.
6-Disable any and ALL anti-virus/malware protection.
7-Run the 15.10 drivers from AMD.com
8-Choose to Install/Express the drivers
9-Restart. Confirm settings are working in windows.
10-Shutdown and add 2nd/3rd cards for Xfire.
11-Respond to this ticket if you have any further questions
** If you have nvidia drivers on your computer, you might need to run the Uninstall feature of Nvidias driver as well.