Yes that will easily power your build, is even fairly overkill.
Edit: didn't see the 3x gtx 980 ti;s
in that case then no, you'd be looking more in the range of 1200 watts
I really dont know dude, I saw someone with the same specs (except running two titan x's instead of 3 980 ti's) and could power it with a 1000 watt power supply.https://www.youtube.com/watch?v=JApehOE5PrI
Here is the build, Im confused, man..