Quote from: Sir Alan on October 04, 2014, 01:48:03 PM

Quote from: manitu on October 04, 2014, 10:27:15 AM

Quote from: frankenmint on October 04, 2014, 10:15:53 AM

Quote from: manitu on October 04, 2014, 10:13:28 AM

Hi,
I need to set higher difficulty for my miners. How can I do that? Now I have diff from 1,4k-1,8k and need about 2k.
Thx.

What software are you using? Could be possible to do in the firmware or possibly on the workers page in Slush's Pool Settings

I am using Antminer S4 devices. How it is possible to change diff on Slush Pool? I can not find this setting.

The pool sets the difficulty. The facility to set it manually on the workers page was removed a good while ago when the auto setting was implemented. Why would you wish to set it higher, other than to reduce your bandwidth?

Because there is a problem with the S4's never getting up to anywhere near their 2TH capability on a pool unless that pool lets them set the minimum difficulty to 2048. I don't pretend to understand it... something about an underpowered controller board and a death spiral dance it does with vardiff. But the the upshot is I can't point my S4 at slush's pool unless they bring back some way of specifying my per-worker minimum difficulty setting :-(

And I just had a very sad few days at BTC Guild... now i have to try GHash -- I would just like to keep ALL my terahashes here at the Slushiest Pool of Them All :-)

This guys can explain it better (a coupla quotes from the Antminer S4 topic):

Quote from: ckolivas on October 08, 2014, 12:09:30 PM

Quote from: PatMan on October 08, 2014, 12:01:40 PM

I'm a little confused tbh, as ck says:

Quote from: ckolivas on October 07, 2014, 10:26:59 AM

It turns out the controller is so low powered that it can only process ~30 shares per second which mean that unless diff is set higher, they work their way into a death spiral before diff catches up. Great...

Which to me sounds like a hardware issue - or is it the firmware that decides how much power is provided to the controller?

It's not a firmware issue. The controller hardware they bundle with it is not fast enough to handle running at low diffs, and most pools start at a lower diff for a while before vardiff pushes them up. If they stay low diff long enough the controller never catches up. I gave them a driver code workaround (i.e. hack) to get over this hurdle. It means they'll (appear to) run at low hashrates for a while until the pool reaches a diff suitable for the device. When they say it's a firmware issue, they mean they'll offer new firmware with an updated cgminer to address the issue.

Quote from: ckolivas on October 08, 2014, 11:47:15 AM

Quote from: ImogenV on October 08, 2014, 11:45:32 AM

Quote from: ckolivas on October 07, 2014, 10:26:59 AM

It turns out the controller is so low powered that it can only process ~30 shares per second which mean that unless diff is set higher, they work their way into a death spiral before diff catches up. Great...

(quoted from another thread)

Is this a problem if one is using an S4 with solo.ckpool.org?

No. S4s work fine here.

Quote from: ckolivas on October 07, 2014, 11:26:55 AM

Quote from: dogie on October 07, 2014, 11:15:50 AM

Quote from: BIGBullion on October 03, 2014, 12:10:04 PM

I did a buy on the S4's and their hashrate locally is 2th/s or greater (awesome!) however, when connected to BTCGuild NONE of them show anywhere close to 2 Th/s. They show more like 200 Gh/s. I have 2 that are over 1 Th/s, but the rest between 0 - 278 GH/s. WTF Bitmain? Huh

The fix for now is to use GHash or BTCGuild with 2048 difficulty. Pools with vardiff seem to overload the miners at the start when spamming them with difficulty 16 shares. A new firmware is on the way soon^TM.

Not quite. Rapidly adapting vardiffs also do fine as the ckpool based pools do, but yes they'll hopefully bring out new firmware with the changes I gave them.