Quote from: smracer on April 26, 2014, 01:18:20 PM

Quote from: Ranma13 on April 26, 2014, 12:39:16 PM

I'm running 20 Gridseeds off a Raspberry Pi and did the 49.9k mod and 5V fan mod to each of them. When I use bfgminer with a clock speed of 1200 MHz, even though the app reports that I'm hashing around 10 MH/s, my pool only reports about 5.5 MH/s.

When I use sandor's cpuminer with autotune on and at 1200 MHz, the results are better. My pool reports 8.5 MH/s, but this isn't quite up to 10 MH/s. I'd expect my hashrate to be in the mid 9 MH/s range; my rejected share percentage is only around 1-3%.

Tomorrow I'm gonna try running two Raspberry Pi's with 10 Gridseeds each to see if the combined speed is higher than running one Raspberry Pi with 20 Gridseeds, but does anybody have any ideas on how I can increase the hashrate to match what I expect? I have 80 Gridseeds in all, and if I'm losing 1.5 MH/s on 20 Gridseeds, that's 6 MH/s across all 80. That's equivalent to buying another 16 unmodified Gridseeds, which is not an insignificant amount.

Are you getting HW errors? I was only able to run the Gridseeds at 1200Mhz after I did the 49.9K mod and I put removed the stock thermal pad from the bottom of the board and applied non-conductive diamond thermal compound. Still not all of them will run at 1200. I run them at 1175Mhz with no HW errors.

Only a few hardware errors. The autotune takes care of optimizing the clock speed.