Bitcoin Forum

I recently picked up a few USB Block Erupters and they've been working great until the past few days. It seems that randomly CGMiner shows their hashrate in ph/s when they should be mh/s and when this happens the overall accepted shares amount freezes even though CGMiner also tells me each Block Erupter is still accepting shares. No hardware errors come up, and things keep running like they would normally except I know that it's not really mining because I checked my wallet and the shares that CGMiner says each USB is mining doesn't come up. I have to keep restarting CGMiner to get the Block Erupters back to their normal hashrate and to get the amount of overall accepted shares to go up again. The weird thing is my average hashrate still stays the same when this happens. What do I do?

Are you using the old -S COMx method (cgminer <= 3.1.x) or the new USB ASIC support method (it was called AMU or something, cgminer >= 3.2)?
I had similar issues with hashrate suddenly going up (mine would freeze instead of showing "fake shares" as you described, however) when I tried the newer cgminer binaries (3.2) that did not require the USB to UART driver, so if you are using 3.2x to mine maybe you could try using the older COM port method by reverting to cgminer 3.1.1 and installing the USB to UART driver.

If these hashrate fluctuations + freeze still continue though maybe you have a faulty unit.

I'll vouch for what jimmielin said. I also had to revert to 3.1.1 with Block Erupters. This worked for me.

I have no idea what the OP problem is that he's having/had.

But I just wanted to say that CGMiner 3.3.1, Win7, USB 2.0 Hubs and  with 15 Block Erupters in 3 miner instances is working great for me and has been for 2 1/2 weeks now.

Allot of people have been reporting problems but I just haven't seen them.
Sam

The problem where your USB miner turns to an extremely high hashrate without submitting shares is a problem of your USB hub. It is probably low quality/faulty. I had this problem with those cheap chinese 10 port USB hubs. I got some more expensive usb 3.0 hubs with 60 watt power adapters and they mine all day long no problem.

I also had issues running cgminer with the USB Block Eruptors.  After much research and frustration, I found where someone else was having the same issues and switched to BFGMiner.  I tried that on mine, and all of my issues cleared up.  It looks like the cgminer developers are working to understand/resolve the issues with the block eruptors, but for now I'm a BFGMiner convert.

Also reverted to 3.1.1. and works superb ... several days without restarting ... error rate <1%, everything fine