What This Error Means
A “Low Hashrate” condition — also described as “hashrate drop,” “hashrate below expected,” “miner underperforming,” or seeing your miner produce significantly less than its rated hashrate — means one or more hashboards are not performing at their designed capacity. Unlike hard errors that produce clear error messages, low hashrate is often a gradual degradation that miners notice when checking their pool dashboard or miner status page.
Every ASIC miner has a rated hashrate — for example, an Antminer S19 Pro is rated at 110 TH/s. If your miner consistently reports 80 TH/s or shows significant variance, something is reducing performance. The cause could be as simple as thermal throttling or as serious as chip-level failures. Hashrate loss directly translates to lost mining revenue, making this one of the most economically impactful issues to diagnose.
Common Causes
- Thermal throttling — The miner is running too hot and automatically reducing clock frequency to lower temperatures. This is the most common cause of gradual hashrate loss and is often invisible unless you check temperature readings.
- Dead or underperforming ASIC chips — Individual chips on the hashboard have failed or degraded, reducing the board’s total hashing capacity. Each dead chip reduces total hashrate by a predictable amount.
- Firmware or frequency misconfiguration — The miner is running at a lower frequency than its rated speed, either due to incorrect settings, a firmware bug, or an auto-tune feature that has downclocked for stability.
- Power supply degradation — The PSU can no longer deliver full rated wattage, forcing the miner to reduce power consumption (and therefore hashrate) to match available power.
- Dust and airflow restriction — Dust accumulation on heatsinks reduces cooling efficiency, triggering thermal throttling at lower ambient temperatures than when the miner was clean.
- Pool-side reporting variance — Normal statistical variance in mining means pool-reported hashrate fluctuates. Short-term drops of 10-20% can be normal; sustained drops indicate a real hardware issue.
Step-by-Step Fix
Step 1: Establish Your Baseline
Before troubleshooting, determine what hashrate you should be seeing. Check the specifications for your exact miner model and firmware version. Note that different firmware (stock Bitmain vs. Braiins OS+ vs. Vnish) can produce different hashrates for the same hardware. Compare your actual hashrate against the specification for your specific configuration.
Step 2: Check Per-Chain Hashrate
In the miner web interface, look at the hashrate per chain (per hashboard). Each chain should produce roughly one-third of the total rated hashrate. If one chain is significantly lower than the others, that hashboard has the issue. If all three chains are equally reduced, the cause is likely system-wide (thermal, PSU, or firmware).
Step 3: Monitor Temperatures
Check chip and board temperatures for all chains. If any chain shows temperatures above the throttling threshold (typically 85-90C chip temperature on most models), thermal throttling is reducing your hashrate. Clean the miner, improve airflow, or reduce ambient temperature. See our Temp Too High troubleshooting guide for detailed thermal solutions.
Step 4: Check ASIC Chip Status
In the web interface, navigate to the chip status or ASIC status page. This shows a grid of all chips on each hashboard, typically color-coded: green for working chips, red or X for dead chips. Count the dead chips. Each dead chip reduces hashrate proportionally — for example, on an S19 Pro with 76 chips per board, each dead chip costs roughly 0.48 TH/s.
Step 5: Verify Frequency Settings
Check the miner configuration for the operating frequency. Compare against the factory default for your model. If the frequency has been reduced (either manually or by auto-tune), this directly reduces hashrate. If you or previous firmware set a lower frequency for stability, there may be an underlying hardware issue that prevented stable operation at full speed.
Step 6: Clean the Miner
Power off and clean all heatsinks, fans, and board surfaces with compressed air. Even a thin layer of dust can increase operating temperatures by 5-10C, which can trigger throttling. After cleaning, power on and monitor if hashrate returns to expected levels.
Step 7: Test PSU Output Under Load
If you have a multimeter, check the PSU output voltage while the miner is running under full load. If the voltage sags below the PSU specification, the PSU is degrading and cannot supply enough power for full-speed operation. A watt meter at the wall can also help — compare actual power draw against the model’s rated consumption.
Step 8: Reflash Firmware
Download and install the latest firmware for your model. Firmware updates sometimes include improved chip performance profiles, bug fixes for auto-tune algorithms, and better thermal management. A fresh firmware install also eliminates any configuration corruption that may be limiting performance.
Advanced Diagnosis
Via SSH, you can get detailed chip-level performance data:
ssh root@[miner-ip]
# Check real-time hashrate per chain
cat /tmp/freq_config
# Check chip frequency and status
cat /var/log/messages | grep -i "asic"
cat /var/log/messages | grep -i "freq"
# On Braiins OS+
bosminer log | grep -i "hash"Chip-level frequency analysis: On miners with per-chip frequency tuning (S17+, S19 series with auto-tune firmware), check if individual chips have been downclocked. A chip that was downclocked by auto-tune is showing early signs of degradation — it could not maintain stability at full frequency. These chips may eventually fail completely.
Hardware error rate: Check the HW (hardware error) count in the miner status. A high HW error rate (above 1-2% of total shares) indicates chip-level problems that are wasting hashing cycles. Each hardware error is a computed share that failed validation, representing wasted energy and lost hashrate.
When to Get Professional Help
Seek professional ASIC repair if:
- Multiple ASIC chips are dead on a hashboard — chip replacement requires micro-soldering equipment and expertise
- Hashrate continues to drop over time despite cleaning and firmware updates — progressive chip failure needs professional diagnosis
- The miner cannot maintain rated frequency even with good cooling — voltage regulator or component failure on the hashboard
- High hardware error rates that do not resolve with firmware updates
D-Central Technologies performs chip-level diagnostics and replacement to restore hashboards to full rated hashrate. We identify and replace dead chips, repair voltage regulators, and optimize performance on all Antminer models. Submit a repair request here
Affected Models
Low hashrate issues affect all ASIC miners. Models particularly prone to gradual hashrate degradation include: S17 and S17 Pro (chip quality issues in some batches), T17 series, older S9 units with high operating hours. The S19 series is generally more stable but still experiences chip failures, especially in units that have been overclocked or operated in hot environments.
Related Error Codes
- ASIC Chip Error / Dead ASIC — Dead chips directly reduce hashrate
- Temp Too High / Over Temperature — Thermal throttling reduces hashrate as a protective measure
- Chain X Only / Missing Hashboard — A completely dead chain causes a 33% hashrate loss
- Voltage Error — Power delivery issues prevent full-speed operation
- PSU Failure — A degrading PSU limits available power
Frequently Asked Questions
How much hashrate variance is normal?
Mining hashrate naturally fluctuates due to the statistical nature of hashing. On the miner itself, expect 3-5% variance on a 15-minute average. Pool-reported hashrate can vary more widely — 10-15% swings on an hourly average are normal. Judge your hashrate on a 24-hour rolling average. If the 24-hour average is more than 5% below rated, investigate.
Does ambient temperature affect hashrate?
Yes, significantly. As ambient temperature rises, chip temperatures rise, and the firmware may reduce clock frequency to prevent overheating. A miner that produces 110 TH/s in a 20C room may produce only 95 TH/s in a 35C room due to thermal throttling. Seasonal hashrate changes are common in environments without climate control.
Can overclocking cause long-term hashrate degradation?
Yes. Running chips above their rated voltage and frequency accelerates electromigration and thermal stress, shortening chip lifespan. A miner that was overclocked for months may have more dead or degraded chips than one that ran at stock settings. If you have been overclocking and notice declining hashrate, return to stock settings and assess chip health.
Should I replace individual dead chips or the entire hashboard?
For 1-5 dead chips, individual chip replacement is cost-effective and typically restores the board to full performance. For boards with 10+ dead chips or voltage regulator damage, board replacement may be more economical. Contact D-Central for a diagnosis — we will assess the board and recommend the most cost-effective path.