For those getting excited about the power usage reported by GPU-z --- Don't!That value is only for the GPU chip its self, it doesn't account for the rest of the board. When my GPU-z shows 83w draw from the 480, my actual measurements taken from the riser and the 6 pin are
141w, a difference of 60 watts!
Here's confirmation from the creator of GPU-z himself:
https://www.reddit.com/r/Amd/comments/4qk17o/my_xfx_480_power_draw/d4tp4hc Are you the one that posted on the reddit ?
You said you got 83w and 88w from pcie slot. So total 171Watts and not 141Watts.
Also since you have some Tahiti cards can you post how much they consume so I can compare it to the 480 in terms of power consumption.
People have been posting power consumption rates anywhere from 120-200watts using 25mh/s and hard to find a value to compare too.