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Antminer S19 Underclock

The honest answer to “Antminer S19 underclock settings”: set a watt target of 1,630 W — the floor of the 126 TH bin’s library and also its best-efficiency point (24.3 J/TH), at half the 3,250 W factory rating. The 88–95 TH factory bin has its own set with a 1,500 W floor at 23.4 J/TH — the bins are covered separately below because mixing them fakes precision. S19 firmware stores no frequency/voltage settings to copy; you set the target and the autotuner does the rest.

Quick answer

The Antminer S19 (126 TH) tunes across a 1,630–4,700 W envelope (Normal mode: 67–130 TH/s). Best catalog efficiency is 24.3 J/TH, and the sweet spot — everything within 5% of it — spans 1,630–1,920 W. The floor is 1,630 W — 50% of the 3,250 W factory rating. There are no frequency/voltage settings to copy: you set a watt target and the firmware autotuner derives the rest for your unit. Status: Verified (extraction).

Best efficiency sits at or near the envelope floor: the lowest watt target your hashrate goal tolerates is also the most efficient point in the catalog.

Antminer S19 (126 TH) — Normal mode Verified (extraction)

1,630 W – 4,700 Wwatt envelope
67 TH/s – 130 TH/shashrate span
24.3 J/THbest efficiency @ 1,630 W
1,630 W – 1,920 Wsweet spot (≤5% off best)
Risingcurve shape
14catalog points

Floor fits a 120 V 20 A continuous-load budget (1,920 W) but not 15 A. Budgets are the NEC 80% continuous-load rule; circuit fit only — stock Bitmain APW-series PSUs require 200–240 V input, so any 120 V build needs a PSU change regardless of watt target. At the floor this mode dissipates about 5,562 BTU/h (watts × 3.412).

Antminer S19 (88-95 TH) — Normal mode Verified (extraction)

1,500 W – 4,000 Wwatt envelope
64 TH/s – 110 TH/shashrate span
23.4 J/THbest efficiency @ 1,500 W
1,500 W – 1,500 Wsweet spot (≤5% off best)
Risingcurve shape
15catalog points

Floor fits a 120 V 20 A continuous-load budget (1,920 W) but not 15 A. Budgets are the NEC 80% continuous-load rule; circuit fit only — stock Bitmain APW-series PSUs require 200–240 V input, so any 120 V build needs a PSU change regardless of watt target. At the floor this mode dissipates about 5,118 BTU/h (watts × 3.412).

Source: Firmware-extraction set for the 126 TH factory bin. The 88-95 TH bin is a separate record (separate factory configuration).

How to set a power target on this model

Aftermarket firmware exposes underclocking as a power target (sometimes "power limit" or a preset picker), not as frequency/voltage fields. Pick a watt figure inside the envelope above; the autotuner benchmarks your boards and settles onto it over a tuning period. Braiins OS+, VNish and LuxOS each expose this in their own UI, and DCENT_OS uses watt-target autotuning on its supported models; the undervolting guide walks through the firmware side step by step, and the firmware comparison covers which firmware supports which model. Verify the result at the wall with a meter — the target is an input, the wall draw is the fact.

Frequency and voltage are calculated at runtime by the firmware autotuner — never fixed presets; per-unit silicon quality, ambient temperature and cooling shift real results.

These envelopes are derived aggregates (bounds, bands, counts) — the row-level operating points, the interactive picker and the CSV/JSON of the source data live in the ASIC Power Profiles Database, the single source dataset for every number on this page.

Antminer S19 (126 TH) full specifications → · Row-level operating points (source dataset) → · Overclock headroom by cooling → · All tuning envelopes →

Related products, repair, and setup paths

Last reviewed August 13, 2026.