Alright, you're in luck. I happen to have this board and recently borrowed a UPS from work to test the draw from the wall with my gear. Here's what I collected:

PSU Load Data via "APC Back-UPS Pro 1000"

ASUS P8z68-V Motherboard with an i5 and 8GB of random memory
GIGABYTE Radeon R9 280X on PCIe x16 slot
Voltage: 1.075
GPU Clock: 1020MHz   Memory: 1500

118watts IDLE
316watts Mining
330-360watt Spikes