HELP! Hashrate drops significantly on Bitfury - impossible to bring it up MAYDAY

[drgyoza]

Hi experts !

My brand new Bitfury hashrate dropped recently from normal (-/+ 410gH after a few days running) to badass (120gH since 10 hours). and i found no reason for it. It was mining on ghash.io then I though it might be linked to some pool factors so I decided to moove it back to btcguild but nothing changed. I tried to tune up modifying difficulty settings but nothing happened.
The noncerate hashrate has dropped to, but in a less significant way. Rebooting the device doesn't help. I doubt chips tuning could help so as the rig is only working 3 days so it should not get dammaged so soon. The thing is that with the actual settings it was able to mine at 500gH and even higher rates sometimes. I it is quite stressful it stopped so as I am supposed to be in my golden mining lapse.

Do you think PSU could be pointed here ?

I mine with 16 bitfury H-cards for a total guaranteed hashrate of 400gH, supplied by a 750w gold seasonic.

I lurked on the forum I found similar problems but not exactly the same. I am quite new to this so maybe the answer is abvious, nevertheless I would really appreciate your advices !

Thank you

 

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[CoinHoarder]

Hrm. This is not exactly how I envisioned this going. This is very frustrating.. my Avalons and KNCminers I was able to setup and get hashing within minutes. Add the assembly time of a full rig, plus the fact they're both not working....

I got two full rigs today. One is running at 225 Gh and the other is running at 0 Gh.

Code:

Rig 1:
Bank 1
1: 33.415GH/s
2: 33.443GH/s
3: 20.702GH/s
4: 21.79GH/s
Bank 2
5: 4.223GH/s
6: 0GH/s
7: 0GH/s
8: 0GH/s
Bank 3
9: 15.677GH/s
10: 10.107GH/s
11: 11.167GH/s
12: 13.758GH/s
Bank 4
13: 9.621GH/s
14: 9.893GH/s
15: 10.165GH/s
16: 20.916GH/s

Rig 2:
Bank 1
1: 0GH/s
2: 0GH/s
3: 0GH/s
4: 0GH/s
Bank 2
5: 0GH/s
6: 0GH/s
7: 0GH/s
8: 0GH/s
Bank 3
9: 0GH/s
10: 0GH/s
11: 0GH/s
12: 0GH/s
Bank 4
13: 0GH/s
14: 0GH/s
15: 0GH/s
16: 0GH/s

I'm certain everything is hooked up correctly. I have checked several times. I tried replacing the PSU and that didn't do anything. I am using a 1200w to run both full rigs. I'm sorry if this is covered... (I'm going to go back and read through this thread now.) Any quick suggestions though? This thread is so long..

I'm not sure if this matters, but it seems the two rigs might have different firmware versions. One says this on the main admin screen the other does not: "Attention! Please set pool difficulty on your pool to 32-512 depending on your hashrate. Low difficulty setting will result in work queue overload, and drop your hashrate substantially. If running a full unit, please make sure all cards are installed in slots written on the back side of the card. Due to SPI bugs, the miner may need to be stopped and restarted using the buttons above."

How I fixed my problems (two rigs stable 473 Gh and 517 Gh- with 1 dead h board on the slower one):

(I don't take credit for these fixes, some of them I found out on my own and some of them I read from other user's experiences.)

I needed to find a way to keep the cards stable, they come with crappy 1x PCI connectors and are really wobbly, especially when being blasted by fans (which is necc. to keep them cool and stable). The movement in the cards was causing the rig to slow down slowly over time until the affected cards eventually ended up at 0 Gh. To fix this I used two rows of electrical tape along the top of the cards to hold them in place better.

Cooling may or may not have been an issue. I added an extra box fan in front (two box fans now) and also two computer fans blowing air down on top of them for added air flow.

I was under the impression that two full rigs would run on one 1200 watt power supply. It turns out that seemed to be overloading the PSU (a nice gold rated ASUS). I ended up using a separate PSU for each rig and that got them both mining. I think this is the main reason why the one was getting 0 Gh and wouldn't mine. As soon as I put it on its own PSU it started working fine.

I put slower H cards in the last slot of each bank to keep them from interfering with other H cards. If you have one bank that is not working but all the rest are, this is likely the issue. If the card in the first slot of each bank is not seated properly, the rest of the bank will not work.

I hope this helps someone and saves them the 16 hours of their life that I just wasted. Now... I wish I would of realized all this before spending all night messing with firmwares... flashing sdcards... installing a different OS... trying BFGminer... trying cgminer... etc. :rolleyes:

My phone messed up while uploading, but a couple pics: http://imgur.com/a/9vDAm#apBFVy5

If I had to guess, the problem I bolded is likely the cause of your problem.

[vm1990]

id agree with that or cooling as op hasnt said anything about any cooling. always better to make sur devices cant slip out of position. iv even seen these problems solved with things as simple as lego

[drgyoza]

I took a few days to answer back in order to analyse the situation properly. It seems to have been caused by cooling deficiency indeed. After a few modifiactions of the cooling system things went much better. Thanks to both of you for the advices.