Windoze 8.1 and multiple GPU's

[wbmillerkc]

Has anyone had any problems getting windoze 8.1 to run a 3rd GPU?
I have a Gigabyte 990 FXA-UD3 mobo
Vishera CPU
8 gig ram
3x spphire r9 280x
1000w Corsair gold PSU.
everything is new.

Set up will run fine with 2 GPU installed, but when I add the 3rd one, windows will detect it, freeze and go to black screen. I can run any 2 of the 3 cards with no problem, it only pops up when I add the 3rd card.

I have the AMD 13.12 and AMD APP SKD installed, and I know a lot of folks run this setup.... So it has to be a Windows problem, but I don't know what I'm missing.

SGMiner runs just fine with the 2 GPU's, I get about 600-630 k/h right out of the box with no tuning other than setting I-20