Same issue here.
ASRock X99 Extreme4
i7 5820K
2 x Crucial Ballistix Sport DDR4-2400 DIMM CL16-16-16
GTX 980 JetStream 4GB
Plugged all together. Inclusive the ATX 12V Slots (2x4).
Pushed the RAM Sticks hard in.
Connected power cable. Turned on. Nothing. No fans, no leds. Absolutely nothing.
PSU...