Quote from: edonkey on March 12, 2014, 01:35:42 PM

Quote from: dualminer_3 on March 11, 2014, 11:09:53 PM

The HW error is expected, especially, when DM works above 850Mhz.
The HW error means a returned nonce result does NOT meet the mining target requirement (if you know some mining theory) . This could happen in some cases:
1. The chip could do a wrong calculation. If it is overclocked, the chip could generate more error. That's why 850MHz will give more errors than 800Mhz.
2. Some errors could happen in the communication between DM device and cgminer. Something like uart buffer overflow.

Since higher clock frequency could introduce instability of the electronic signal, most of HW error is caused by the first reason.

HW error is different to the reject error. Reject error is caused by mining pool. If a new block had been generated and DM was still working on previous job, some nonces of previous job maybe still queued in a buffer of cgminer. If cgminer submit these old result to pool, the pool will reject them.

Thanks for getting back to me dualminer_3. I realize that rejects are different than hardware errors. And I also realize that some number of hardware errors is expected with Dual Miners. I'm just interested in whether I'm seeing an expected hardware error rate.

I've been running cgminer for 20 hours without the "--dualminer-pll 850" command line and have had a total of 53 errors across 20 units. If I assume that this rate is fairly consistent, then I can estimate that I would see an average of 3 hardware errors per unit per day.

Is that a reasonable and expected rate?

If it isn't, then what can I do to diagnose and fix this?

Remember that I mentioned that I have two fans plugged into the same USB hubs where I have Dual Miners. Could these be making electrical noise or cause power fluctuations? If so, I can move them to a dedicated hub.

Thanks in advance for any further advice you might have.

From my experience as long as your error are spread about, it seems to be a reasonable/expected rate currently. If you have a spare hub it may not be a bad idea to separate your DMs from fans that may pull lots of energy/create lots of vibration.