Known issue with ethash "suboptimal shares"

[Steve Sokolowski]

There is currently a known issue involving "suboptimal shares" with ethash mining. A "suboptimal share" is defined as a share where the merge-mined portion is stale, but the primary coin is not, so the share is partially credited. Because ethash mining doesn't allow for merge mined coins, the term "suboptimal" has no meaning for ethash coins.

This is a complex issue that is expected to require significant investigation. We are currently awaiting a reply from one of several customers, all of whom were asked to provide the timezone where the computers with which they accessed the website were located. If you encountered a "suboptimal share" and want to remove this block, you can submit the exact time it occurred, down to the second, along with the timezone, and the username of the account where it was recorded, in a support ticket. We need to obtain the exact time of one share before we can continue this investigation, and the first customer to reply or submit a ticket will allow us to continue.

We confirmed that no money is being lost, so mining continues as normal. It's possible that miners weren't credited enough money, and if so, you can continue mining and will be given more money should the investigation reveal that share corrections are required.

We hope to have a resolution by May 19 or 20.

[Varlot]

Hello, I am getting suboptimal shares from time to time. I have seen it going even up to 50% sometimes. ATM it is 20%.

How would one detect the suboptimal share? I am using SRBminer and all of the shares have been shown as accepted so I have no idea how to go about this.

Also if it is determined that the shares weren't paid in full because of this problem do I need to submit a ticket to get reimbursed or will it be automatic?

Sorry if this is something that is known, I am in fact a noob miner, been mining for 3 months of which one month on Prohashing.

Thank You for Your time.

[Banished_Privateer]

Suboptimal shares are also heavily related to mining software and overclocking. It's been noticed that if people overclock their GPU before generation of DAG file, it will result in about 10-20% suboptimal/stale shares. Depending on what software you use, it's adviced to first generate DAG file and afterwards overclock the device (if you do overclock, of course).

[mrhaidenevans1]

I've noticed that over the last few days my coins generated has pretty much halved even though my MH/s rate has remained unchanged... how would I hunt down these suboptimal shares? I'm using GMiner if that's any help.

Thanks in advance

[Steve Sokolowski]

I've noticed that over the last few days my coins generated has pretty much halved even though my MH/s rate has remained unchanged... how would I hunt down these suboptimal shares? I'm using GMiner if that's any help.

Thanks in advance

Unfortunately, it's more likely that you aren't making as much money because of the market's trend reversal, rather than because of any bugs in the system.

Coin prices have declined by 30%, and hashrate on networks continues to increase, squeezing margins for mining.

[cryptomined]

My AMD rig running gminer has been rock steady. Only change in output has come from ETH price fluxuation.

[Varlot]

Suboptimal shares are also heavily related to mining software and overclocking. It's been noticed that if people overclock their GPU before generation of DAG file, it will result in about 10-20% suboptimal/stale shares. Depending on what software you use, it's adviced to first generate DAG file and afterwards overclock the device (if you do overclock, of course).

Thanks for the advice. As I said previously in mining software I am using all of the shares are accepted. I rarely get rejected, invalid or stale shares. Maybe one in a week or even longer periods.

None the less I have tried out first starting up the software without overclock and waited several seconds for it to generate DAG file and only after it was generated did I apply the overclock. The suboptimal share problem still persists.

I do have to say it is not that I get that all the time but from time to time it will show from 20-50% suboptimal shares in pie chart on the dashboard.

OCD part of me dislikes that so much but if I am not damaged financially for that I can live with it.

One more thing. I am getting around the projected whattomine profitability for ethash so I don't feel like there is money lost and if it is it's in pennies range per day. Still would love to see the issue resolved or at least be assured that it is not an actual problem.

[Steve Sokolowski]

Suboptimal shares are also heavily related to mining software and overclocking. It's been noticed that if people overclock their GPU before generation of DAG file, it will result in about 10-20% suboptimal/stale shares. Depending on what software you use, it's adviced to first generate DAG file and afterwards overclock the device (if you do overclock, of course).

Thanks for the advice. As I said previously in mining software I am using all of the shares are accepted. I rarely get rejected, invalid or stale shares. Maybe one in a week or even longer periods.

None the less I have tried out first starting up the software without overclock and waited several seconds for it to generate DAG file and only after it was generated did I apply the overclock. The suboptimal share problem still persists.

I do have to say it is not that I get that all the time but from time to time it will show from 20-50% suboptimal shares in pie chart on the dashboard.

OCD part of me dislikes that so much but if I am not damaged financially for that I can live with it.

One more thing. I am getting around the projected whattomine profitability for ethash so I don't feel like there is money lost and if it is it's in pennies range per day. Still would love to see the issue resolved or at least be assured that it is not an actual problem.

I'm hoping to have more information by Monday. Right now, I'm leaning towards that there isn't any money actually being lost, and the shares are simply being incorrectly reported.

[ElectricEnigma]

Has any progress been made on why the ethash says suboptimal shares? A few times a day I see where Im as low as mid 90s on efficiency because of suboptimal shares. Thanks in advance!

[Steve Sokolowski]

Has any progress been made on why the ethash says suboptimal shares? A few times a day I see where Im as low as mid 90s on efficiency because of suboptimal shares. Thanks in advance!

I think that this issue is related to the memory issue. Shares become suboptimal for a few minutes after each restart, since new blocks aren't being sent to you.

That new memory should arrive tomorrow. I suggest submitting a support ticket if, after three days from now, the issue persists. I don't think it will.