Learn why an ASIC miner may show unstable or lower-than-expected hashrate in PECPool. This guide explains how to compare current, 1-hour, and 24-hour hashrate, identify network, cooling, power, firmware, hashboard, and rejected-share problems, and restore stable mining performance.
Unstable or lower-than-expected hashrate can reduce mining efficiency and daily Bitcoin earnings. The miner may remain Online in PECPool while its effective pool-side hashrate stays below the normal performance expected from the device.
Low hashrate does not always mean that the mining pool has a problem. The cause may be related to normal short-term share variance, worker downtime, network instability, rejected shares, temperature, electrical power, firmware, performance settings, or one or more hashboards.
This guide explains how to determine whether a hashrate change is normal, how to compare local and PECPool hashrate correctly, and how to troubleshoot unstable or persistently low performance in Antminer, WhatsMiner, and other compatible Bitcoin SHA-256 ASIC miners.
Hashrate is the number of SHA-256 calculations a Bitcoin mining device performs every second. It represents the miner's computational power.
Bitcoin ASIC hashrate is commonly measured in:
Individual Bitcoin ASIC miners are commonly measured in TH/s, while larger mining accounts or farms may be displayed in PH/s.
The hashrate displayed in the miner's local interface and the hashrate displayed in PECPool are calculated differently.
The miner estimates performance from internal ASIC-chip operation, calculated results, frequency, and device statistics.
Depending on the manufacturer, local values may be labeled:
PECPool estimates effective hashrate from valid mining shares actually received from the worker over time.
This means the local interface shows what the miner reports it is calculating, while PECPool shows the effective mining work reaching the pool.
A temporary difference between these values is normal. A persistent and significant difference should be investigated.
Different hashrate values should be used for different types of analysis.
| Hashrate Type | Meaning | Best Use |
|---|---|---|
| Current Hashrate | Short-term estimate from recent share activity | Checking immediate mining activity |
| 1-Hour Hashrate | Average performance over a recent period | Checking short-term stability |
| 24-Hour Hashrate | Longer effective average | Evaluating general miner performance |
Do not diagnose a miner only from the Current Hashrate value. Short-term share submission is naturally variable and can temporarily produce values above or below the miner's rated performance.
A miner may be considered underperforming when its longer effective average remains significantly below its normal or rated performance after allowing enough time for share statistics to stabilize.
Before deciding that hashrate is low, confirm that:
Pool-side hashrate is estimated from mining shares, and shares are not submitted at perfectly equal intervals.
A healthy miner may submit several shares close together and then take longer to submit the next share. This can temporarily make the Current Hashrate move above or below the expected value.
Normal behavior may include:
Persistent low averages, repeated large drops, long chart gaps, or frequent restarts are more likely to indicate a real problem.
A newly connected or restarted miner requires time to initialize its hashboards, connect to the stratum server, and submit enough valid shares for a reliable pool-side estimate.
A practical process is:
Do not compare a miner that restarted a few minutes ago with another miner that has been running continuously for an entire day.
Open the PECPool Monitor section and review the affected worker.
Check:
If the worker is Offline, troubleshoot the pool connection before investigating minor hashrate differences.
Accepted shares confirm that PECPool is receiving valid mining work from the worker.
If accepted shares are increasing normally but Current Hashrate fluctuates, the change may be normal short-term variance.
If accepted shares stop increasing, the pool-side hashrate will decrease and may eventually reach zero.
Check the miner's local status page for:
A miner can display normal local hashrate while its PECPool hashrate remains lower because too many submitted shares are not accepted.
Rejected or stale shares may increase because of:
Review the exact rejection reason in the miner's system or kernel log before changing unrelated settings.
The PECPool hashrate chart can reveal patterns that are not obvious from a single value.
Small movements around the expected hashrate are normally caused by natural share variance.
Long periods at zero normally indicate that PECPool did not receive valid shares during that period.
Possible causes include:
Repeated drops may indicate:
A gradual decrease may be related to:
Open the miner's IP address in a browser and review its status page.
Depending on the firmware, the page may be called:
Check:
Many Bitcoin ASIC miners contain multiple hashboards. If one board is missing or unstable, the miner's total hashrate may decrease significantly.
For example, a miner designed with three hashboards may lose approximately one part of its expected performance when one board stops operating.
Check that:
Hashboard repairs should be performed only by qualified technicians using procedures suitable for the exact miner model.
Hardware errors indicate that some ASIC calculations were not completed correctly.
A small amount of hardware error activity may occur on some miners, but an unusually high or rapidly increasing value can indicate instability.
Possible causes include:
High hardware errors may reduce effective hashrate and increase invalid-share submissions.
Excessive temperature can cause ASIC chips to reduce performance, become unstable, or trigger protective shutdowns and restarts.
Check that:
Use the operating limits published for the exact miner model. Do not apply one universal temperature limit to every ASIC device.
A fan problem may cause high temperature, reduced performance, protection mode, or repeated restarts.
Check:
Do not operate an air-cooled ASIC miner with a failed or disconnected required fan.
Dust accumulation restricts airflow and increases heat.
Inspect:
Power down the device safely before cleaning and use a maintenance method appropriate for the exact miner model and environment.
ASIC miners require stable electrical power. Voltage drops, overloaded circuits, damaged connectors, or insufficient power supplies can cause low hashrate and repeated restarts.
Check:
Immediately investigate loose, damaged, discolored, or overheated electrical connections.
A weak or failing power supply may not provide sufficient stable power to all hashboards.
Possible signs include:
Use only a compatible power supply with sufficient capacity for the miner and its configured performance mode.
Overclocking increases frequency to produce higher local hashrate, but aggressive settings can make the miner unstable.
Possible results include:
If instability began after applying a performance profile, return the miner to its previous stable or factory-supported setting and monitor the result.
Undervolting can reduce power consumption, but insufficient voltage may cause unstable ASIC operation.
Symptoms may include:
If the issue began after changing voltage settings, return to a known stable profile and compare the result.
Firmware controls pool communication, ASIC frequency, voltage, cooling, hashboard detection, and share submission.
Firmware problems may cause:
Recommended practices:
A miner can show normal current hashrate while its 24-hour average remains low because it restarted several times earlier.
Check:
Repeated restarts reduce average hashrate even when the miner performs normally between restarts.
Network problems can reduce effective pool-side hashrate while local miner hashrate remains normal.
Possible signs include:
Inspect:
From Windows:
nslookup btc-eu.pecpool.comFrom Windows PowerShell:
Resolve-DnsName btc-eu.pecpool.comFrom Linux:
getent hosts btc-eu.pecpool.comThe test should return an IP address. If it does not, review the network and DNS configuration.
From Windows PowerShell:
Test-NetConnection btc-eu.pecpool.com -Port 3333Look for:
TcpTestSucceeded : TrueFrom Linux:
nc -vz btc-eu.pecpool.com 3333If one port is blocked or unstable, test another supported PECPool port for the selected region.
A server with slightly higher latency but stable routing may perform better than a server with lower latency and frequent packet loss.
Official PECPool Bitcoin stratum servers include:
| Region | Server | Available Ports |
|---|---|---|
| Global | btc.pecpool.com |
3333, 443, 25 |
| United States | btc-us.pecpool.com |
3333, 443, 25 |
| Europe | btc-eu.pecpool.com |
3333, 443, 25 |
| Russia | btc-ru.pecpool.com |
3333, 443, 25 |
| Asia | btc-as.pecpool.com |
8443, 443, 25 |
| Iran | btc-ir.pecpool.com |
8443, 443, 25 |
| Iran Alternative | btc.pecpool.cc |
8443, 443, 25 |
Configure Pool 1, Pool 2, and Pool 3 to reduce downtime during a connection problem.
Example:
URL: stratum+tcp://btc-eu.pecpool.com:3333
Worker: myaccount.miner01
Password: xURL: stratum+tcp://btc.pecpool.com:443
Worker: myaccount.miner01
Password: xURL: stratum+tcp://btc-us.pecpool.com:25
Worker: myaccount.miner01
Password: xUse the same worker identity for all three entries of the same physical miner.
Frequent switching between Pool 1, Pool 2, and Pool 3 can create short mining interruptions and reduce effective hashrate.
Check:
If Pool 2 remains more stable than Pool 1, move the stable address to the primary position after completing sufficient testing.
A mining proxy can reduce the number of external connections, but an overloaded proxy may delay mining jobs and share submissions.
Check:
When practical, temporarily connect one affected miner directly to PECPool. If performance improves, investigate the proxy or its network path.
If other miners on the same network operate normally, focus on the affected miner.
Check:
When many miners are affected at approximately the same time, investigate shared infrastructure.
Check:
Suppose a miner shows:
| Value | Hashrate |
|---|---|
| Current Hashrate | 104 TH/s |
| 1-Hour Hashrate | 99 TH/s |
| 24-Hour Hashrate | 73 TH/s |
This pattern may indicate that the miner is currently operating normally but experienced downtime earlier during the previous 24 hours.
Review the chart and restart history before changing miner settings.
Suppose a miner normally produces approximately 120 TH/s but displays:
The lower hashrate is caused by the miner hardware rather than the stratum connection. Check the missing board, power connections, signal cables, firmware, and power supply.
Suppose a miner displays:
The miner is calculating locally, but too much useful work is being lost because of the network connection.
Investigate:
Before overclocking:
Local Hashrate: 100 TH/s
PECPool 24-Hour Hashrate: 98 TH/s
Restarts: NoneAfter overclocking:
Local Hashrate: 112 TH/s
PECPool 24-Hour Hashrate: 92 TH/s
Hardware Errors: High
Restarts: FrequentThe higher local peak hashrate did not produce better effective performance. Returning to the stable profile may improve the PECPool average and mining efficiency.
Changing the server, firmware, frequency, voltage, cooling, and network equipment at the same time makes it difficult to identify the real cause.
Use a controlled process:
| Symptom | Likely Cause | Primary Check |
|---|---|---|
| Current hashrate fluctuates | Normal short-term share variance | Review 1-hour and 24-hour averages |
| Local and pool hashrate both low | Miner hardware, cooling, power, or settings | Check hashboards and miner status |
| Local hashrate normal, pool hashrate low | Rejected shares or network instability | Check shares, latency, and packet loss |
| Hashrate drops by a large fixed amount | Missing hashboard | Check chain and board detection |
| Repeated chart drops | Restarts, overheating, power, or network | Check logs and uptime |
| 24-hour average low but current normal | Previous downtime | Review the 24-hour chart |
The highest momentary local hashrate is not always the best mining result. A stable miner with low rejected shares and continuous uptime can produce better effective performance than an aggressively configured miner that frequently restarts or submits invalid work.
Use the PECPool 1-hour and 24-hour averages together with accepted shares, worker status, last-share time, and the hashrate chart.
When the longer averages remain low, troubleshoot the problem in a controlled order: network, shares, hashboards, temperature, power, firmware, and performance settings.
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