I personally have had lots of troubles in the past, with Nvidia and AMD, when it comes to running multiple monitors with the use of HDMI. I can't even get two monitors to work if one is HDMI.
This was exactly the problem it wouldn't run 3 displays with the HDMI port. =\
Anyway got it going with the 28" going DVI-->DVI-->HDMI
And Using the DVI--> HDMI cable for the TV..
I wish I could get sound running thru the TV though.
Another day another problem.