Quote from: strangerhacks on April 26, 2014, 09:07:09 AM

I have 10 Antminer U2's that I was running at 1.6GH/s when I got them, after my Arctic Breeze fans came in, I overclocked them to 2.2GH/s and now recently I noticed you can just keep going, there's overclock support for up to 4GH/s if you can get it working with proper cooling.

Now when I found out about these new values for overclocking further then the "supported" 2.2GHz (x0A81), I decided I would start testing slowly one step up at at time until I notice the heat increase so I stepped them up to 2.4GH/s (x0B81) and ran those for about a week, didn't heat up at all, the fans are keeping the heat sinks cold to the touch from ambient room temperature.

The problem though, is earlier tonight I decided it's time for the next step and upped it to 2.6GH/s with x4C81 only to have crazy hardware errors (something around 13-15% on boot and they just kept climbing). After this happened, I would have to disconnect everything, plug each hub back in with nothing in them, and plug each Antminer U2 back in the hubs one at a time while the hub was powered on just to get all 10 working again otherwise only 4 would come up if I tried to open my .bat file again after changing the overclock value back down.

So does anyone know why my Antminer U2's run flawless at 2.4GH/s (x0B18) but as soon as they're set to 2.6GH/s (x4C81) they go crazy and then only 4 work until I unhook everything and hook them up one at a time? They're handing 2.4GH/s just fine, still cold even so I don't see why 2.6GH/s would be so glitchy when they're barely even making heat with how I have them cooled.

EDIT:
I forgot to add, I tried 2.8GH/s just to see if maybe it was a 2.6GH/s issue, perhaps skip it and go on to the next but that wasn't the case, as soon as I opened BFG Miner when set to 2.8GH/s (x4D81) they went from all 0 to 100% hardware errors instantly.

I just don't understand why it's such a drastic jump in issues. I've been back on 2.4GH/s for about a half hour now and I still have 0 hardware errors but 0.2GH/s more and it jumps to a 13-15% starting rate for hardware errors and keeps going up, then another 0.2GH/s more and they start off at 100% hardware error.

Can you increase a voltage. They need more juice in my opinion
Volt mod or something