Bitcoin Forum

Most of the pools suggest something like using diff. 1 for CPU or single GPU mining, 2 for multiple GPU, 4 for 2-4GH/s etc.  My question is if you have multiple asicminer block erupters running in cgminer as a worker, do you choose a difficulty of 1 based on each erupter doing 336MH/s or would you choose a difficulty setting based on the cumulative speed? 

Example:
1 block erupter - diff 1
3 block erupters - diff 1
6 block erupters - diff 1

or

1 block erupter - diff 1
3 block erupters - diff 2
6 block erupters - diff 4

So more specifically does the work load truly get distributed across all the devices running in an instance of cgminer or does each device still do its own work at its own speed?  The line by line output makes me think that the work is considered "many 336MH/s devices" vs. a single 2GH/s device if you had 6 of them.

It's a cumulative hash rate per worker that matters.  So select the base difficulty rate of all your erupters added together on each worker.  I selected a base difficulty of 2 for a worker with 5 Block Erupters even though Diff1 would have been fine too.

It's a bit of a subjective thing too.  If you want to use less bandwidth on your internet connection increase your base difficulty.
Sam

So other than creating more traffic than necessary (which could affect the pool servers and yourself) does being able to hash at a higher difficulty not pay off any better than at 1?

When I see shares accepted in cgminer and it says something other than 1/1 (for example 2/1 or 16/1) I assume I get credited for one share, correct?  Is seeing things higher than 1/1 any kind of indication that a higher difficulty would be beneficial?   

And also, what happens when too high a difficulty is chosen?  Do you see your payout rates go down as you maybe aren't able to solve shares as quickly?  So if I have a good idea of what my combined erupters will do at diff 1 then I just need to make sure I don't see a decline in accepted shares over the same amount of time at a higher difficulty?

Nope, unless your using the POT payout method on Ozcoin which is bit like gambling.


Correct


Not really, if you see one over 31.3M it will be a block solver.  


Just higher variance.  It should still even out over time.


Your payout could vary up or down.  But, again, it should even out over time.


No, if you set your difficulty to 2 you will submit half the number of shares but they will be converted to diff1 shares by the pool and you will be paid on that estimate.  If you set your difficulty to 4 you will submit 1/4th the number of shares and so on.

Whew,  that must be a record number of questions in such a short space. :)
Hope it helps,
Sam

Haha, sorry, but thanks for the clarification!

Thanks from me too, are some days that i'm searching for an answer to the same question.

Thank You !  :)

Me too, seriously thanks! lol.  Was not going to be that guy lol.

Oh, so now I'm that guy  ;D

I had questions about this as well after I added my USB Block Eruptors.  I was running a difficulty of 1, and then changed it to 8 on one miner and 16 on the other.  In my experience, the reported hash rate on the mining server swung wildly, and I wasn't ever able to tell if I had miner issues or not.  From what I read, if bandwidth is not a concern, then a difficulty setting of 1 should result in more uniform hash rate readings on the mining server.  To confirm how much bandwidth was actually being used I installed a neat little program on Linux called 'iftop'.

Yes, the higher you set your difficulty the more variance you will have, as you described.

Most pools have variable difficulty so they will adjust the difficulty of work they send you on the fly.  If you have a very high hashrate device/worker then it's good for the pool to increase your base difficulty.  BTC Guilds site has a pretty good scale for that, which you could apply to any pool.
Sam

Organofcorti did an analysis and found that variance would be kept to 1% if share return rate is 20-24 per minute. You return one share per minute on average per 71.6Mhash. So you get to 24 shares at 1.7GH. Using 1% variance as an arbitrary target, that means you should increase your diff by 1 for every 6 Erupters.

Was not my question but have been looking for the answer, thanks for the explanation and the questions