Low Hashrate — Troubleshooting Guide

Overview

Low hashrate is the single most common complaint from ASIC miner operators. A miner producing 10–50% below its rated specification is losing revenue every hour. The causes range from trivial (wrong firmware setting) to serious (degraded ASIC chips), and a systematic approach is essential to avoid wasting time on the wrong fix.

This guide covers all major causes of low hashrate across Antminer, Whatsminer, and Avalon miners, ordered from most likely to least likely.

Symptoms

Low hashrate manifests in several patterns, each pointing toward different root causes:

• Steady low hashrate (e.g., 160 TH/s instead of 200 TH/s) — usually missing chips or a disabled voltage domain
• Gradually declining hashrate over weeks or months — thermal paste degradation, aging chips, or accumulating dust
• Fluctuating hashrate swinging between normal and low — thermal throttling, intermittent connection, or pool-side issues
• Hashrate normal at miner but low at pool — high reject/stale rate, network latency, or incorrect pool configuration
• One board significantly lower than others — board-specific hardware issue

Quick Checks

Before detailed diagnostics, these quick checks resolve the most common causes in minutes:

Diagnostic Flowchart

Hashrate below specification
│
├─ Are all chips detected? (check chip count)
│  ├─ NO → See "Missing Chips" section below.
│  │       Also see: Missing Chips Troubleshooting (/docs/troubleshooting/missing-chips)
│  └─ YES ↓
│
├─ Is the miner thermally throttling? (check chip temps)
│  ├─ YES → Address cooling issue. Clean heatsinks, check fans,
│  │        check thermal paste, reduce ambient temp.
│  │        See: High Temperature (/docs/troubleshooting/high-temperature)
│  └─ NO ↓
│
├─ Is the frequency at the expected value?
│  ├─ NO → Check firmware settings. Restore default profile
│  │       or adjust frequency to rated value.
│  └─ YES ↓
│
├─ Is the pool reject rate above 2%?
│  ├─ YES → Check network latency, pool URL (use closest server),
│  │        difficulty setting, and firmware version.
│  │        See: High Reject Rate (/docs/troubleshooting/high-reject-rate)
│  └─ NO ↓
│
├─ Is one board significantly lower than the other two?
│  ├─ YES → Board-specific issue. Check for partially failed
│  │        voltage domains, degraded thermal paste on that board,
│  │        or loose connector.
│  │        See: Abnormal Chip Voltage (/docs/troubleshooting/abnormal-chip-voltage)
│  └─ NO ↓
│
└─ All boards equally low, all chips present, no throttling,
   correct frequency, low rejects → Possible chip degradation
   over time, or PSU not delivering full power.
   Measure PSU voltage under load.

Causes (Ordered by Probability)

1. Missing or Non-Responding Chips

Probability: ~30% | Impact: Proportional to missing chip count

Missing chips are the most common cause of low hashrate. Each chip contributes an equal share of the total hashrate, so missing chips directly reduce output.

How to identify: Compare the chip count per board in the web UI against the expected value from the tables above. On Antminer, the "ASIC Status" page shows each chip as an "o" (working) or "x" (missing). On Whatsminer, the hash board status page shows chip counts per board.

Common reasons chips go missing:

• Failed ASIC chip (open circuit or short) breaks the daisy chain
• Cold solder joint on a chip
• Broken CLK/CI/RI signal trace
• Voltage domain failure taking out a group of chips

Fix: See Missing Chips Troubleshooting for a complete diagnostic guide.

2. Thermal Throttling

Probability: ~25% | Impact: 10–40% hashrate reduction

When chip temperatures exceed safe limits, the miner firmware automatically reduces the operating frequency to lower heat output. This is a protective mechanism, not a fault.

How to identify: Check chip temperatures in the web UI. If any chip exceeds 80°C (or the model-specific threshold), throttling is likely active. Also check:

• Ambient temperature above 35°C
• Fans running at 100% speed
• Dust accumulation on heatsinks
• Miner positioned in a recirculating airflow path

Common sub-causes:

Fix: Address the root thermal cause. For thermal paste replacement, see your model-specific repair guide. For fan issues, see Fan Error Troubleshooting.

3. Firmware Misconfiguration

Probability: ~15% | Impact: Variable, up to 50%

Incorrect firmware settings are surprisingly common, especially after firmware updates, factory resets, or when using third-party firmware.

Things to check:

• Frequency setting: Ensure it matches the rated frequency for your model
• Power limit: Some firmware allows setting a wattage limit that caps hashrate
• Mining mode: "Efficiency" or "Low Power" modes intentionally reduce hashrate by 20–40% in exchange for better J/TH
• Auto-tune: If using Braiins OS+ or similar, the auto-tuner may still be ramping up (takes 1–24 hours to reach full hashrate)
• Voltage override: Manual voltage settings that are too low will limit maximum stable frequency

4. Pool-Side Issues (High Reject/Stale Rate)

Probability: ~12% | Impact: Up to 5–15% effective hashrate loss

The miner may be hashing at full speed locally, but the pool rejects a significant portion of submitted shares. This shows as lower-than-expected hashrate on the pool dashboard.

How to identify: Compare the miner's locally reported hashrate with the pool-reported hashrate. If the miner shows 200 TH/s but the pool shows 170 TH/s, the difference is lost to rejects and stales.

Common causes of high reject rate:

• Network latency: Use a pool server geographically close to your miner
• Vardiff too high: Some pools set variable difficulty too aggressively — try a different pool
• Stale shares: Slow network delivery means your miner works on outdated block templates
• Wrong stratum URL: Using Stratum V1 when V2 is available, or using an incorrect port
• DNS issues: The miner cannot reliably resolve the pool hostname

Fix: See High Reject Rate Troubleshooting for detailed diagnostics.

5. PSU Underperformance

Probability: ~8% | Impact: 5–30% hashrate reduction

If the PSU cannot deliver rated power, the miner firmware reduces hashrate to match available power. This is common with aging PSUs, undersized PSUs, or high-altitude installations (reduced cooling efficiency).

How to identify:

• Measure PSU output voltage under full load — if it drops below spec, the PSU is struggling
• Check PSU fan — if it runs at maximum speed constantly, the PSU is near its thermal limit
• Try running only two boards — if hashrate per board increases, the PSU is the bottleneck

Fix: Replace the PSU or reduce the miner's power target to match the PSU's actual capacity.

6. Chip Degradation (Aging)

Probability: ~5% | Impact: Gradual, 5–20% over the chip's lifetime

ASIC chips degrade over time due to electromigration and thermal cycling. After 18–36 months of continuous operation, some chips may no longer be able to maintain their rated frequency, resulting in automatic downclocking.

How to identify: Hashrate has been slowly declining over months with no configuration changes. All chips are detected, temperatures are normal, and frequency is correct. Individual chip hashrate (visible in some firmware) shows some chips contributing less than others.

Fix: There is no repair for chip degradation. Options include:

• Accept the reduced hashrate
• Replace the hashboard
• Overclock surviving chips to compensate (increases failure risk)

7. Network and Connectivity Issues

Probability: ~5% | Impact: Intermittent drops

Network problems cause the miner to disconnect from the pool, losing mining time. This appears as fluctuating hashrate on the pool dashboard.

How to identify: Check the miner's uptime and connection log. Look for frequent pool disconnections and reconnections. Ping the miner from another device — if packet loss exceeds 1%, you have a network issue.

Fix: Check Ethernet cable and connections, replace the cable if damaged, ensure the switch/router port is functioning, and verify DHCP is assigning a stable IP address.

Normal Hashrate Ranges by Model

When to Seek Professional Help

Consider professional assistance if:

• Hashrate is below 70% of specification after you have checked all causes in this guide
• Multiple boards are affected and you have ruled out PSU, cooling, and firmware
• You suspect chip degradation but want confirmation before investing in replacement boards
• The miner shows full chip count, normal temperatures, correct frequency, low reject rate, and good PSU voltage — but hashrate is still low (may indicate a control board FPGA or firmware issue)

Frequently Asked Questions

My pool hashrate is lower than my miner hashrate — is something wrong?

Pool-reported hashrate is a statistical estimate based on submitted shares. It naturally fluctuates around the true hashrate. Over a 24-hour period, pool hashrate should average within 3–5% of the miner's reported hashrate. Short-term fluctuations of 10–15% are normal.

Does ambient temperature affect hashrate?

Yes. Every 10°C increase in ambient temperature can reduce hashrate by 3–8% due to thermal throttling. ASIC miners are rated for operation at 25–35°C ambient. Above 40°C, significant throttling is expected.

Can a bad Ethernet cable cause low hashrate?

A bad cable causes intermittent pool disconnections, resulting in lost mining time. The miner's local hashrate will appear normal, but the pool-side hashrate will be lower due to missed share submissions. Replace the cable if you see frequent reconnections in the miner log.

Should I overclock to compensate for low hashrate?

Only if you have identified and resolved the root cause first. Overclocking a miner with missing chips, thermal issues, or a weak PSU will make the problem worse. If the miner is healthy but you want more hashrate, overclock conservatively (5–10% above stock) and monitor temperatures closely.

How long should I wait after a firmware update before judging hashrate?

Allow at least 30 minutes for the miner to stabilize after a firmware update. If using auto-tuning firmware like Braiins OS+, allow 6–24 hours for the tuner to optimize. Do not compare pool hashrate until at least 4 hours of stable operation.

Related Guides

• Missing Chips Troubleshooting
• High Temperature Troubleshooting
• Fan Error Troubleshooting
• Abnormal Chip Voltage
• High Reject Rate Troubleshooting
• How Hash Boards Work
• Antminer Error Codes
• Whatsminer Fault Codes