Why is the hashrate shown in the mining pool lower than the local hashrate of the miner?

The hashrate displayed by the mining pool being lower than the hashrate of the local miner might be due to many factors. The common reasons are as follows.

Normal hashrate loss

Miners should note the possibility that not all local hashrate measured by your machines will be converted to valid hashrate for pools, which contributes to finding a block. This could lead to a huge difference.  Especially mining with GPU devices, these factors below may lead to normal hashrate loss.

• Network latency: Network latency will cause a small percentage of hashrate loss due to a failure of submitting hashrate from the miner to the mining pool.
• Devfee setting on mining software: 0.5% to 2% of the hashrate will be deducted and converted into developer fees.
• Excessive overclocking: Excessive overclocking will lead to a big loss on hashrate. It’s possible for overclocking to cause hashrate abnormalities without the presence of high reject rates and other anomalies.

Generally, between the local hashrate and the 24-hour average hashrate of the mining pool courts, the normal range of error rate is within 5% for GPU, and 2% for ASIC. 

Abnormal hashrate loss

If the deviation between the local hashrate and the hashrate displayed on the mining pool is too large, please check the rejection rate and the hardware settings.

• If the rejection rate is comparatively high, it is usually due to network issues. It leads to the low submission of hashrate from your local miners to the mining pool. You may check your routers, switches, network cables, interfaces, etc., in order to define the issue.
• If the rejection rate is normal, please check the hardware of the miner. If there is overclocking, try to restart the miner, replace the hashrate board, and reduce the frequency in order to solve the problem.