Topic: Butterfly Labs - Bitforce Single and Mini Rig Box - page 36. (Read 186944 times)

So 830mh/s of bfl will produce same number of shares as 830mh/s of GPU?  Then what's the big deal?  That there is a theoretical loss of hashing power because some shares are aborted?

Actually no.
It will report 26% less shares since it aborts 26% of shares before you see them.

No it will produce the expected # of shares however you will have a 26% stale rate.  Actually a little higher because you have the normal stales due to network propogation too.  This is borne out in observations by users reporting a DOA & orphan combined rate of something like 30% to 40% of hashing power.

Does this mean that you would expect with a BFL FPGA to generate 26% fewer shares at a given hash rate than a GPU?

Yeah I've explained it a few times already (elsewhere?) but I'll do it again

The BFL does not report shares until it finishes processing the full nonce range.
So about 5.2 seconds (assuming 830MH/s) after it starts on work it replies with the answer(s).
If during that 5.2 seconds you get an LP then anything it did during that 5.2 seconds is wasted.

What that means is that on average for every LP your BFL will have wasted 2.6 seconds processing.
The miner code should/will then of course abort the work so that it doesn't continue to finish the remainder of the 5.2 seconds, but the work done up to the abort is wasted since you cannot ask it if it found a share (and it didn't tell you even though it would have been a valid share if it had already found it)

Since LP's occur on expected average of every 10 seconds ... and on expected average you waste 2.6 seconds processing ... that's 26% of your processing is thrown away (and you can't avoid it)

As SgtSpike mentioned, the issue cannot be fixed with cgminer settings (or any mining software settings) ... BFL must create/release new firmware (which they have not yet done) for the Singles to be able to work 'successfully' with p2pool.

Until that happens, you must choose a different pool. Or choose different mining hardware.

It's impossible to run it with p2pool right now...

Is anyone sucessfully running their BFL Singles against p2pool? I understand the frequent LONGPOLL's cause a problem with BFL's 5 second calculation. (By successful, I don't just mean that it works, I mean it works efficiently and you are making the normal amount of coin as expected). If so, can you share your settings for CGMiner?

   Thats a really badass fan  

I was OC'in an old AMD CPU years ago & screwed one of these to it:

http://www.newegg.com/Product/Product.aspx?Item=N82E16811999612

I can't remember what CPU it was,but that thing worked like a charm.I do remember the CPU never got over 50c @ about a 25% OC.But god was it LOUD!!!!!!


"Maybe try this next.
http://www.newark.com/sanyo-denki/9cr1212g002/counter-rotating-axial-fan/dp/96M1717
with an adapter to fit the 120mm fan in place
http://www.newegg.com/Product/Product.aspx?Item=N82E16811996022
 


  Does it come with a chipper attachment

I knew where that was going...

I am laughing at the bits of wires that are being sucked into the new fan when turned on. Be careful, you already broke one

300 CFM!!!! A little more and you'll be ready for lift off.

Maybe try this next.
http://www.newark.com/sanyo-denki/9cr1212g002/counter-rotating-axial-fan/dp/96M1717
with an adapter to fit the 120mm fan in place
http://www.newegg.com/Product/Product.aspx?Item=N82E16811996022
 

It's a Delta TSB series fan from an old server power supply. Probably about 5K RPM.

lol, nice!  Is that an 8000 rpm fan?  What model is it?

I thought that too at first, but upon closer investigation the improvement is clear, they have increased cooling capacity.

I have highlighted the VRM area in Yellow, this area needs airflow to cool down. On the original revision they could not use a bigger heatsink as it would have blocked the airflow to this area, but with the heatpipe they were able to add an additional heatsink and keeping the VRM area cooled.

Man all you guys moaning about the noise these things make... damn. I decided to make a video just for you:

https://vimeo.com/41028028

I accidentally set the thing down on something that was sticking up, and it got caught in the fan and broke the blades off. So I decided to give it some real cooling.

Thanks for that; a quiet fan puts the Single in a totally different light. I've experimented with the following fans on my Rev2 (dual fan) and Rev3 (single fan, heatpipe) Singles and can share some thoughts:

Ixtrema IXP-64-14G (1600rpm, 42cfm, 14dba)
Ixtrema IXP-64-14R (1600rpm, 42cfm, 14dba)
Silenx Effizio EFX-09-15 (1600rpm, 42cfm, 15dba)
Antec TriCool High (2200rpm, 38cfm, 27dba)
Silenx Effizio EFX-09-12 (1300rpm, 32cfm, 12dba)
Vantec Stealth (1750rpm, 28cfm, 20dba)
Antec TriCool Med (1600rpm, 28cfm, 21dba)
Antec TriCool Low (1200rpm, 21cfm, 15dba)
Evercool EGF-9 (1200rpm, 24cfm, 16dba)

If your ambient isn't too high (say, 75F or lower) I've had good luck with the EFX-09-15; it is very quiet and moves a decent amount of air. Not as much as the stock fans (contrary to its specs), but it might be sufficient depending on your ambient temperature. I'll be replacing most/all of my stock fans with these.

The slower/quieter EFX-09-12 doesn't have quite enough airflow to keep the Singles from throttling.

My 2 Ixtrema's don't like being in a horizontal orientation and start to make clicking noises. I'm not sure it is just my 2 particular samples, or if this is a common failing of this model. Otherwise they seem as if they might be a good alternative.

The TriCool is interesting because you can set it to 3 different speeds ('low' is too low; 'medium' might be ok, but there are better fan options on this list at this performance level; 'high' is louder than stock).

The Evercool doesn't have sufficient airflow (even less than the EFX-09-12).

The Vantec Stealth is relatively loud compared to the rest of these but still quieter than the stock fan; it moves more air than the EFX-09-15 contrary to the specs so it may be another reasonable alternative.

I haven't been able to source the Noiseblocker BlackSilent Pro in in my neck of the woods.

A few days ago I replaced the fan of my Rev. 3 unit with a 'Noiseblocker BlackSilent Pro Fan PE-P - 92mm'. Temperature now is stable at 58°C - 61°C. There is no throttling, average speed is at 820Mh/s. The solution is not perfect as you still can't sleep right next to it, but it is much better than before.

I will say this: the Sunons on the Rev3 Singles, though loud, do have that alluringly sweet sound of a fully stocked datacenter humming away!  It is a high-quality white noise.