As an update to this issue, I was able to get CrossFire to work with two cards enabled for about 2 hours with the Insane texture settings before the game crashed. Three cards runs briefly before stuttering. 4 cards enabled results in nearly immediate stuttering that progressively gets worse after 2-3 minutes followed with the Windows notification regarding memory usage Oddly enough, the Windows memory error seems to be fairly generic and would suggest that the PC is out of memory rather than the GPU(s). The insane texture settings didn't seem to slow the game down (FPS >130-140FPS) with 16X Antistropic filter and 4x MSAA with V-SYNC disabled. Very-High settings will probably resolve the memory issue with only 2 cards enabled.
Right Click - AMD Settings -> About - "Radeon Additional Settings" -> CrossFire settings -> CrossFire 2 GPUS 0+6, 0+8, 0+4, 0+10, etc...
Unfortunately there's no way to edit the TitanFall profile to perform the switch from CrossFire mode with 2 GPUS enabled when launching the game so this has to be done manually. Both BF3 and BF4 have no problems with 4 cards enabled. Going to experiment with their profiles later.
