Quote from: gusti on May 20, 2011, 11:44:05 AM

Sorry, I do not see your point that power over capital investment cost changes with difficult. Can you please ellaborate or give a practical example ?

Today, you buy $2000 worth of hardware. Your hash rate is 1500 MH/s. You draw 1200 watts. A bitcoin is worth $7. Electricity is $0.10/kWh. You gross $1228 a month and your electricity cost is $86 a month. Your electricity cost is just noise.

Imagine that a year from now, the difficulty is tenfold.

At this point a FPGA rig is going to have a fraction of your power consumption. At that point:
Your hash rate is 1500 MH/s. You draw 1200 watts. You gross $123 a month and your electricity cost is $86 a month. Your net profit is $37/month. Your electricity cost consumes most of your gross.

The guy with the FPGA array has the same hash rate of 1500 MH/s. He draws 300 watts. He grosses $123 a month and his electricity cost is $21 a month. His net profit is $102 a month.

Will difficulty rise tenfold? Will bitcoins continue to be worth $7? Will 1500MH/s of hashing power only draw 300 watts in FPGAs? Who knows? I'm just pointing out the scenario where the FPGA guy can have a huge advantage.

Quote from: Basiley on May 20, 2011, 07:52:03 AM

but at that "reach point" you need FPGA-utilising solution with multiple FPGA's per board or use them into mini-boards[ISA bus ? Tongue

], stacked into main one, to minimise communication/power/connectivity impact on solution cost.
and also, board must be ready to put into industry-adopted-sizes racks[both IT and manufacturing/science racks meant]. if you plan to sell number of such boards.

Well, yeah. I don't think that anyone is proposing that FPGA reference boards are the way to go. The way to go is to do your own board design and load it up with bucketfuls of FPGAs.