Have you got 5x 290 Tri-x setup yet?
Interested to see if they are stable, as the R9 290's are hit and miss with more than 3.
bump
I have 4 running stable paired with 4GB of ram and the cheapest LGA1150 CPU.
Pulling a consistent 945KH/s+ on 3 cards, and over 900KH/s on 1 card (which won't take the memory overclock... yet), straight out of the box with no burn-in.
I see no reason I couldn't add a fifth (other then that I can get other 290 cards for cheaper, so I won't bother)
(Rejects are almost entirely because of vardiff causing Share below target)