I have been acquiring hardware to build a couple of mining rigs. Newegg.com and Tigerdirect, where I usually order parts from, are both out of stock in the higher end graphics cards. I did find a couple for sale on ebay, the bids were already over $900. Newegg shows 4 cards in the mid $700 to $800 + range. I asked to be notified when they become available.
I am wondering if AMD is seeing a big increase in demand for their high end cards and if so when the supply might increase. I also would like to know more about their plans for the next generation of high end cards. Specifically if they can reduce the power consumption it would dramatically affect the mining profitability.
It is also apparent that the cost of electricity to run the build rigs is quite significant. Since these cards draw 900 watts at rated output and I pay $0.15 per KwH for power, running one for 24 hours costs about $3.60 a day. If the machines reside in AC space that will add more load to the AC. In Florida this is already high.
So running one high end rig for a month is likely to increase my bill by at least $100. I even looked into adding some Solar PV capability to my home to offset the increase in power costs.
Building and operating these mining rigs makes economic sense, at least a little bit, and especially if one expects the value of bitcoins to rise dramatically in the future. However it is fun, at least for some of us.