I honestly don't think its possible to implement SHA256 on 1k LUTs that's discussed by these FPGA dev boards in this post. (Let alone an implementation that's going to beat out traditional CPUs or GPUs).
Like seriously: 1k x 4-LUTs means that these iCE40 FPGAs has 4096-total inputs to all of their logic. SHA256 has ya know, 256-bits of input and probably takes more than 16 "steps" to implement even with a perfectly route. (But if anyone proves me wrong, consider me happy).
You're thinking orders of magnitude too big here. The FPGAs described in this post are much, much, much smaller.
mrb
Oh, right, not 1k LUTs. But toward the $120 range, such as the Digilent Arty S7 listed in the post, with 23k LUTs, it's likely possible to implement SHA256 cracking or mining and beat a CPU or GPU in performance/watt. Probably not performance/dollar though.
Like seriously: 1k x 4-LUTs means that these iCE40 FPGAs has 4096-total inputs to all of their logic. SHA256 has ya know, 256-bits of input and probably takes more than 16 "steps" to implement even with a perfectly route. (But if anyone proves me wrong, consider me happy).
You're thinking orders of magnitude too big here. The FPGAs described in this post are much, much, much smaller.