I've done the voltage mod with 49.9kohm resistors and the 5V fan mod on 8 of my Gridseeds, but I'm having a problem. I'm using the Hashra image with a Raspberry Pi, but the Gridseeds are only stable up to 950 MHz. What's weird is, they run perfectly fine at 950 MHz, but the moment I try bumping it up to 1000 MHz, they basically fail to hash at all. To give an idea, at 950 MHz, my pool reports ~3.5 MH/s with about a 3-5% reject rate. At 1000 MHz, my pool reports ~0.01 MH/s with a 80-90% reject rate. Any idea what could be causing the problem?
Try this image:
https://github.com/mox235/scriptaThere is a link to an image in the readme. I modded all 10 of mine and they are running at 1200Mhz with 0 rejects and 0 hardware errors. I forked that repo and will be doing some work on that image to make it even better.
It uses a custom cgminer that supports frequencies for each miner so you can tune your rig.