WhatsMiner M30S vs M31S+: Which Should Australian Miners Buy?

MicroBT's WhatsMiner range has earned a strong reputation for build quality and reliability, and both the M30S and M31S+ are solid second-generation machines that still see significant use in home mining setups across Australia. But they're not the same miner — different chip generations, different efficiency figures, and different price points in the second-hand market mean the right choice depends on your electricity rate, budget, and how long you plan to run.

This guide compares the two side by side so you can make a clear, numbers-based decision.

Specifications at a Glance

Both miners include an integrated PSU — one of the defining features of the WhatsMiner design versus Bitmain's Antminer range, which requires a separate power supply on most models. Both run on 200–277V AC, which covers Australia's 240V/50Hz grid without any modification.

Efficiency: The Number That Matters Most in Australia

Australia has some of the highest residential electricity costs in the world. In most states, home miners are paying between $0.28 and $0.38 per kWh, which means a miner's efficiency figure — measured in joules per terahash (J/TH) — has an outsized impact on whether the operation is profitable at all. For context on how electricity rate affects mining economics, see our breakdown of what electricity rate makes home mining profitable in Australia.

The M30S has a clear efficiency advantage: 34–38 J/TH versus the M31S+'s ~40 J/TH. That may not sound like a large gap, but at scale and over time it adds up:

• At 90 TH/s and 3,268W, the M30S draws approximately 2.86 kWh per hour
• At 84 TH/s and 3,360W, the M31S+ draws approximately 3.36 kWh per hour
• Running 24/7, the M30S uses roughly 68.6 kWh per day versus the M31S+'s 80.6 kWh per day
• At $0.30/kWh, that's a difference of roughly $3.60 per day, or about $1,314 per year

The M30S produces more hashrate while consuming less power. On paper, it is the more efficient machine — and that matters significantly on Australian electricity tariffs.

Hashrate: M30S Wins, But Not by a Huge Margin

The M30S produces 90–94 TH/s compared to the M31S+'s 84 TH/s — a difference of roughly 7–12%. In practical terms, this means the M30S earns marginally more block reward share when connected to a mining pool, but the gap is not dramatic enough to be the deciding factor on its own. What matters more is that the M30S achieves its higher hashrate at lower or similar power draw, making the efficiency advantage the more meaningful differentiator.

Worth noting: both machines have ±5% hashrate tolerance from the factory. A low-batch M30S might perform closer to 85–86 TH/s in practice, narrowing the gap with a strong M31S+ unit. Monitor actual performance via your pool's reported hashrate rather than relying on the nameplate spec alone. Our guide on how to read your miner's stats explains what to watch.

Running Costs at Australian Electricity Rates

Here's how the two machines stack up at common Australian electricity tariffs, assuming the M30S runs at 90 TH/s / 3,268W and the M31S+ runs at 84 TH/s / 3,360W:

The daily saving from the M30S's superior efficiency increases as electricity rates rise — meaning the advantage is most meaningful for miners in SA, NSW, or QLD where rates tend to be highest. For a deeper look at how rates vary across states, see our guide on WA vs QLD vs NSW electricity rates for miners.

Chip Architecture: Samsung vs TSMC 8nm

Both miners use 8nm ASIC chips, but from different foundries — the M30S uses Samsung 8nm while the M31S+ uses TSMC 8nm. In practice, both chip generations have proven reliable in real-world deployments. The M30S's Samsung chips have a longer track record given the model's age, and both have well-documented failure modes and repair ecosystems. For Australian miners considering long-term operation, either chip platform is acceptable — what differs more meaningfully is the thermal load each places on the cooling system.

The M30S uses larger 14038 fans (140mm diameter) versus the M31S+'s 12038 fans (120mm diameter). Larger fans move more air at lower RPM, which generally means quieter operation and lower fan stress — a relevant consideration for home mining setups and for longevity in the Australian summer. See our guide on thermal management for ASIC miners in Australian summer conditions.

Resale Value and Market Availability

Both machines are second-generation WhatsMiner units and sit in similar price bands on the Australian used hardware market. Neither will command a strong resale premium — the market for older-generation SHA-256 miners is soft as newer, more efficient units like the Antminer S21 series become more accessible. That said, MicroBT hardware has historically held resale value slightly better than equivalent Bitmain units due to reputation for build quality and fewer reported hash board failures.

If you're buying second-hand, the M30S is the more attractive unit given its efficiency advantage — but inspect carefully. Hash board failures are the most common failure mode on both machines, and replacement boards are a significant additional cost. Our guide to buying new vs second-hand ASIC miners covers what to check before purchasing used hardware. For a broader look at how different ASIC brands compare on resale, see our mining hardware resale value guide.

How MicroBT Compares to Bitmain and Canaan

If you're deciding between brands rather than just between these two models, our detailed comparison of Bitmain vs MicroBT vs Canaan for Australian miners covers the full picture — including support, firmware, and long-term reliability track records.

Which One Should You Buy?

The answer depends primarily on what you're paying for the unit and what you're paying for electricity.

Buy the M30S if:

• It's available at a similar or lower price than the M31S+
• You're on a residential electricity rate above $0.28/kWh and every efficiency point matters
• You want slightly more hashrate for the same or less power draw
• You prefer the larger 14038 fans for noise and longevity reasons

Consider the M31S+ if:

• It's priced meaningfully cheaper than the M30S in your market
• You have access to very low electricity (under $0.20/kWh) and the efficiency gap is less financially significant
• The M30S is unavailable and you need a proven WhatsMiner unit

Consider skipping both if:

• You're deploying new capital and don't need to minimise upfront cost — current-generation machines like the Antminer S21 151 TH/s or Antminer S21 Pro 234 TH/s are dramatically more efficient at 15–17 J/TH and will deliver significantly better returns on Australian electricity rates over a 12–24 month horizon

For context on where these machines sit in the broader market, our data-driven guide to when to upgrade your miner walks through the numbers on continuing versus replacing older-generation hardware.

Bottom Line

Between the two, the WhatsMiner M30S is the better machine — more hashrate, better efficiency, larger cooling fans, and a stronger chip track record. The M31S+ is not a bad miner, but it has no meaningful advantage over the M30S at comparable prices. If you're in the market for a used WhatsMiner and can find a well-maintained M30S at a fair price, it's the stronger buy.

Both the WhatsMiner M30S and WhatsMiner M31S+ are available through MinerHub with Australia-wide shipping and Australian Consumer Law protections. Browse the full range of Bitcoin miners in our Bitcoin miners collection.