including mobo, wifi etc about 350w, I haven't tried to lower it.
*winces* .. Dunno what Mobo/CPU you have, but considering that mining is not CPU intensive, I can't imagine that package is any more than 50W. That would mean ~300W for a single card...?
I can get FEs for an okay price (compared to current retail), but it's only 10% more hashrate for almost twice the power draw of a tuned 56. I'd be extremely interested in the results of any tweaking you end up doing.
It runs about 100W on idle but I made no effort to reduce running power so I reckon about 250w
I work away from home during the week doing well paid IT work so I only get the opportunity to tweak at the weekend and if it falls over during the week I'm not there to fix it and I can lose up to 5 days mining, hence stability wins, but its just a hobby for me