Post
Topic
Board Mining
Re: FPGA mining for fun and profit
by
ArtForz
on 18/05/2011, 00:18:13 UTC
Quote
A single pipeline is now doing about 133MH/s with the chip around 210MH/s total
Trying to make any sense of this.
a) You have a 120+ stage unrolled pipelined engine at 133MHz. You fit 1.58 of em? what the hell is 0.58 of a engine?
b) You have a single registered round running at 133MHz. one bitcoinhash = double-sha256 takes 128 or so clocks. you fit 200 of those - ~ 208Mh/s.
let's assume B
you need to store at least a..h and W 0..15, that's 24*32 = 768 FFs per engine.
times 200 engines. thats 153600 FFs
a S3-5000 has 66560 FFs... nope
a S6 LX100 has 126576 FFs... still nope
a S6 LX150 has 184304 FFs... 83% utilization just for the storage FFs. far edge of plausible

For adder utilization it gets hilarious, you need at least 8 32-bit adders per round.
Times 200 single-round engines thats 1600 32bit adders...
half of a S6s slices have carry logic, each of those can do 4 bits of a adder, that's a max of 988 32 bit adders on a S6 LX100, 1439 on a LX150... we need 1600... ?!?

I have the sneaking suspicion someone didn't realize one bitcoinhash = 2 sha256 blocks...