(sorry for the OT tangent)

5830s overclocked (and carefully clock managed, but not overvoltaged, 324MH/s) bought in bulk, 6x to a board, slowest cpu, network booting, a lot of careful tweaking. All other parts cut to a minimum. GPUs screwed to a wooden frame many linear feet long spaced as wide as possible. Ribbons ordered from hong-kong and shipped on the slow boat. I'm also fairly power efficient for a gpu setup— you can gain a fair bit by careful psu selection and running at 240v.  (and good power quality is important for stability at high clock rates)

Total cost per node are 109*6 (gpus) + 210 (mb) + 4*6 (ribbons) + 60 (cpu/ram)  + 100 (power) + 8 (marginal price of a ethernet switch port) = $1056 plus some modest shipping costs and a negligible amount of wood and screws.  yields 1944 MH/s.  Er. That a bit better than I said, though its a bit closer once you throw in some for shipping.


Its hard to say. There are a lot of gpu miners... and once the cards are a couple generations old I expect an influx of used cards (especially a lot of lemon used cards that have been driven hard and not well cooled as many miners are guilty of) will undermine the used market price. It's hard to guess by how much.  These ATI GPUs are only so vastly superior to the alternatives for a few apps.. a lot of gamers would rather have nvidia.

If you want to build a DES cracker however, then that FPGA will be a pretty smoking solution.  I expect the FPGA vendors could probably improve their sales by offering tools for other applications, just to increase customer confidence that the FPGAs are useful for things other than mining.  DES reversing and WPA cracking are obvious things that come to mind. ... lack of fast IO limits SDR applications, lack of memory and fast IO limits imaging applications, these are best for crypto.