Large number of rejected shares

16/12/2022

Rejected and incorrect shares result from an unstable graphics card's work or poor Internet connection. During mining, the graphics card (GPU) solves mathematical calculations and sends the results to the Kryptex pool.

If the result is incorrect (invalid share) or sent too late (stale share) — the pool will mark it as rejected, and you will have no reward.

How do I know if my computer is sending incorrect shares?

You can go to the Kryptex settings and check the "Show miner windows" checkbox. After that, it is worth waiting for a while for the miner to enter operating mode.

During the usual mining process, the percentage of rejected shares should not exceed 1-2% To get accurate data, you must mine for at least 1 hour (bets for 24 hours). Therefore, the longer a continuous mining session lasts, the more accurate the data.

Types of shares and their differences

In its window, the miner shows the status for each found share. Shares may be labeled differently in different miners, but the meaning is the same:

  1. Share accepted — everything is fine, the pool has accepted a share and it will be paid.
  2. Invalid share — bad share. The GPU made a completely wrong calculation (2+2=5). Usually, such shares are eliminated at the checking stage by a computer and not sent to the pool. On a properly configured GPU, there should be no invalid shares.
  3. Rejected (Stale) share — share was sent to the pool, but the pool rejected it. Most often, this is a share that came to the pool too late, and someone else has already found the same one.

Kryptex does not hide the loss due to the rejected shares. Other pools may do this. It’s quite funny sometimes to read “And pool N has 0% rejects”. It's funny because it can't be like that.

Why can't it be? Consider the example of Ethereum mining.

For each found block, the Ethereum network gives out a reward, which is approximately 0,5 Ether. This amount is pretty stable, although sometimes there are bursts of profitability. You can see it at etherscan in the Reward column. The reward is divided among all miners. But the number of miners is growing https://etherscan.io/chart/hashrate

Why is 0% Rejected shares a scam?

The pool gives all users the same calculation task, and its solution depends on random numbers. So all GPUs begin to solve it at the same time.

Well, almost simultaneously — no one canceled network delays. If the card finds a share, it sends it to the pool. And then there are three possibilities:

  1. Your GPU found the share first and on time. Great — share accepted!
  2. The GPU of some other miner has already found this share. Perhaps its task came earlier because of the fast Internet. In this case, your share is 100% stale. It's a pity, but the work has been in vain in this case.
  3. Nobody found the share in time. Your GPU could not find a share in the allotted time, but after a couple of seconds, it managed to find it and sent it to the pool. This share has a chance to spawn Uncle block. So it is not lost, but the pool must mark it as stale.

As a result, you can't avoid rejects listed in topics 2 and 3 in any way. You will have stale shares, and the more the network delay is (the later the GPU gets work) - the more there will be.

The main reasons for Incorrect shares

  1. Your GPU is overclocked too much. If you are overclocking your GPU, try turning off overclocking completely. If this helps, the overclocking was too aggressive, and you should reduce it.
  2. Defective risers. If connecting the GPU through risers, check their power connections and quality. Try running mining without them and see if the error goes away. The contact between the riser and wires must be reliable. The riser must not hang freely in the motherboard connector.
  3. Poor power supply. The GPU may produce incorrect shares if the power ripple exceeds the allowable limits. Try to install another power supply, more powerful and more reliable.
  4. The GPU has failed. If you have ruled out other causes, the GPU is likely damaged. You can try installing it on another computer. If the problem repeats — it is worth taking it to a service center.

The main reasons for rejected (Stale) shares

During the usual mining process, the percentage of rejected shares should not exceed 1-2%

If the miner shows more, it is worth looking for the reason:

  1. Unstable internet connection. If you have wired internet, contact your ISP. When using mobile Internet or Wi-Fi, delays can also be relatively high. Connect your computer with a cable.
  2. Torrents. Downloading torrents also loads the Internet channel so that shares can be sent with a long delay. Disable torrents and see if the error goes away.

For mining, it is not the speed of the Internet that is important, but the stability and access time — ping. The lower the ping to the Kryptex pool, the higher the probability that the pool will successfully accept your shares. Ping up to 100 milliseconds is considered normal.

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