Why Joules Per Terahash Matters More Than Sticker Hash Rate
A practical guide to evaluating mining hardware efficiency when Korean electricity tariffs eat into margins faster than hash-rate gains.
When operators in Gyeonggi compare two rigs with identical advertised hash rates, the purchase decision often comes down to sticker price per terahash. That shortcut ignores the variable that actually determines monthly profitability: how many joules each terahash consumes under sustained load on a Korean industrial circuit.
The Measurement That Counts
Manufacturer datasheets typically cite hash rate at ideal conditions — cool ambient air, fresh firmware, and a power supply at the upper end of its efficiency curve. In a converted warehouse near Pyeongtaek running 24/7 through a humid August, those numbers drift.
We measure wattage per terahash (J/TH) after a 72-hour sustained run. This captures:
- Fan ramp behaviour as intake temperature rises
- Voltage sag under industrial load sharing
- Firmware auto-tuning that trades hash rate for stability
A rig rated at 110 TH/s that draws 3,400 W performs differently from one rated at 108 TH/s drawing 2,900 W, even though the first looks faster on paper.
Korean Tariff Context
KEPCO industrial rates vary by time-of-use band and contracted capacity. A rig that lands in Class C instead of Class B might add ₩180,000–₩320,000 per month across a 1 PH/s deployment, depending on your contracted tier and operating hours. That gap often exceeds the hardware price difference within the first year of operation.
How to Use Efficiency Classes
Our five-tier classification (A through E) groups rigs by measured J/TH under standard bench conditions. When comparing options:
- Request or commission measured J/TH, not just rated hash rate
- Match the class to your electricity cost per kWh
- Factor in cooling overhead — a Class B rig in a poorly ventilated rack may operate at Class C in practice
A Common Mistake
Operators sometimes overclock firmware to push hash rate up 3–5%, only to find efficiency class drops by a full tier. The extra terahashes rarely cover the added wattage at current Korean tariffs.
If you are weighing two or more models above 0.05 PH/s, a structured comparison report removes guesswork from the procurement conversation.