I currently run between 1500-1600watts with 3x290 overclocked. I believe I was sitting at around 1400watts previous to overclocking.
sempron 140
msi 890fx
8GB ram
300GB HD
3x R9 290
2x1000w psus
hope this helps!
Your PSU must be very inefficient. 3x r9 290x on original power/clocks etc. hashing 2.9 mh/s and consuming 1180 W at wall (it's 90% eff. PSU wchich means whole rig pulls no more than 1100W)
+1. Something way off with that guy's numbers. My 4.4ghz 3570k system with two 290's, not overclock, pull ~650w from the wall when mining. CPU is idle of course.