I could run 3dmarks at 5ghz (3930k) and 2400mhz RAM with Quad Fire at 1260/1600 and I was able to pass the tests. I was using 2600w of PSU. One lepa G 1600 and one EVGA SuperNova 1000W.
I tried everything so far, I have put a couple of weeks in solving the issue and I litterrally tried all drivers for AMD R9 290x cards, all mobo drivers, all Rampage IV BIOS.
I tried Trifire with cards 1-2-3 no issue even at 4.8Ghz CPU, I also tried slot 1-3-4 and no problem. So there is no problem with the power into the slots.
I tried windows 7, windows 8 and windows 8.1
I also tested each card seperatly at 1250/1650 for 2-3 hours each.
I am able to play with my QuadFire but it always crash the game after a certain time.