Regarding logi's comment where is our voltage meter guy when we need him HaHa. Test x11 vs. Hefty. Either way heavycoin wins at currency regardless.
I'll have some numbers tomorrow evening, since I live in Malta and Muniticoin (X11) is launching, just feel obligated to mine it for a few days. But it's probably back to HVC after that.
Anyway, I have 5 rigs, one 4x 280x, one 4x 290, two 4x 270, and one 2x 780ti (my daily rig), all with meters on them.
My meter shows 760Wh of combined power, from 3 rigs with 4 280X OC cards total, that are not too heavily undervolted (~1.14V). That's with the new miner, with the previous one it was 650Wh. Scrypt mining expended about 1300Wh. I get about 14.9 Mh per card, could probably be optimized to squeeze out a little more out of them.