Is this possible? I would like to run three R9 290s on my Gigabyte Z87X UD3H, since I have the PSU to easily handle it, and I'm going to be doing a custom loop. I've been finding conflicting evidence as to whether or not this would work. I don't mind the PCI-E 2.0 X4 bottleneck, as it's been showing as negligible in all of the tests I could find, and used 290s are dirt cheap anyway.
I'm just not sure if it's possible to Crossfire since the third X16 slot is on a separate controller from the other two?
Sources saying it's possible:
http://www.anandtech.com/show/6989/intel-z87-motherboar...
http://www.eteknix.com/gigabyte-z87x-ud3h-z87-motherboa...
http://www.legitreviews.com/gigabyte-z87x-ud3h-intel-z8...
I feel like Anandtech is pretty trustworthy. I'm hoping someone can confirm this for me though, maybe there's someone on Tom's running a tri-fire setup similar to this?