Quote from: george357 on March 25, 2013, 07:57:39 PM

Thanks for the information, deathcode! Your post tells that I am correct in thinking that the GPUs and PSU is the primary consideration in building a mining rig. I will begin my search for 7970/7990s in the new/used/refurbished markets and see what deals I can find. Are other HD7000 series cards pretty good for this as well, as a general rule or are some of them not really suited to this type of usage? I am thinking about assembling this rig on a test bench set-up instead of inside a case which might be more conducive to cooling. I am planning on Four (4) GPUs, is it better to run them in crossfire or set a miner instance for each card?

As far as the cost/profit argument for me its not so much about what I can profit (of course any is good Grin

), I am looking at it more from the helping the cause perspective as well as building a pretty bad-a** computer (another reason to use the test-bench setup; quick upgrade-ability) which is usable for other things, especially if the ASICS do what people seem to think they will to mining.

I think the 7970's are the best bang for the buck as you can find decent ones on ebay for about $300-320 but make sure they are not beaten up by other miners.
7990's can be an option too at 1200Mhash/s but as far as I know only PowerColor makes them and they are hard to find and they seem to occupy more than two PCI-E slots and there are other issues too. like price.
A test bench is fine. I keep my cards in a non crossfire setup, since they won't benefit from it for mining purposes.
Best of luck.