Bitcoin ASIC Chip Evolution: From BM1385 to BM1373

Hold a Bitaxe Gamma in one hand and an old Antminer S7 in the other. Same algorithm. Same SHA-256. Same Bitcoin protocol from the same Satoshi whitepaper. But the silicon at the heart of each device tells a story of 13 years, 13× efficiency improvement, and a fundamental redesign of how mining hardware is built. The S7's BM1385 chip was state-of-the-art in 2015 at 200 J/TH. The Gamma's BM1370 sits at 15 J/TH. And the brand-new BM1373 — Bitmain's first 3nm SHA-256 chip, shipping in the Antminer S23 series — pushes that down to 10 J/TH per chip.

Each generation of ASIC silicon is a story: a process node shrink, a voltage domain redesign, a transistor count that doubles or triples, a thermal envelope reshaped to extract every joule of useful work. Most miners never look inside their hardware. The chips are black squares under heatsinks, anonymous and identical. But understand the silicon, and you understand the entire economics of solo mining: why some chains favor old chips, why a Bitaxe is genuinely different from an industrial farm, why the next halving will hurt some operators and not others.

This is the gufo's complete chip atlas. We'll walk through every major Bitmain mining ASIC from 2015 to 2026, compare them honestly with MicroBT and Auradine offerings, and finish with educated speculation about what comes after BM1373.

What an ASIC chip actually is (briefly)

A Bitcoin mining ASIC — Application-Specific Integrated Circuit — is a chip designed for exactly one purpose: computing the SHA-256 hash function as fast as possible while burning as little power as possible. Unlike a CPU or GPU which is a generalist, an ASIC is a savant. It can do nothing else. But the one thing it does, it does roughly 100,000× faster per watt than a high-end GPU.

Inside the chip are millions of small SHA-256 compute cores running in parallel, each computing one hash per clock cycle. Modern Bitmain chips contain hundreds of thousands of these cores on a single die. Total per-chip throughput is measured in terahashes per second (TH/s), and total efficiency in joules per terahash (J/TH). Lower J/TH = more useful work per watt = lower power bill = competitive miner.

Two physical levers control everything:

1. Process node — How small the transistors are. Smaller = more transistors per square millimeter, lower switching voltage, less heat. Industry has gone from 28nm (BM1385) to 3nm (BM1373) over a decade.
2. Architecture — How the cores are arranged, how they communicate, how power is delivered. Smart architecture extracts more useful work from the same silicon area.

Both improve every generation. Bitmain has shipped 9+ generations of mining chips since 2013. Each one made the previous obsolete in 18-24 months. This is why mining is hard. The hardware competes against itself.

The Bitmain chip family tree

Here's every major Bitmain SHA-256 mining ASIC of the past decade, from oldest to newest, with the device that made each chip famous:

Read that last row twice. From 30 GH/s in 2015 to 2,500 GH/s in 2026. An 83× improvement in per-chip hashrate. From 200 J/TH to 10 J/TH. A 20× improvement in efficiency. The same algorithm. The same network. The same SHA-256 puzzle. Just better silicon, year after year.

Process nodes — what those numbers actually mean

"Process node" is shorthand for the manufacturing technology used to fabricate the chip. The number — 28nm, 7nm, 3nm — historically referred to the smallest feature size on the chip, though modern naming is more marketing than measurement. What matters: smaller numbers mean more transistors fit in the same area, and each transistor switches at lower voltage with less leakage current.

Each node shrink delivers roughly:

• 2× transistor density — twice as many compute cores in the same chip area
• ~30% lower power per operation — less heat for the same work
• ~15-25% higher clock speeds — more hashes per second per core

Combine these and you get the cumulative gains from BM1385 to BM1373:

BM1385 (28nm, 2015): 30 GH/s, 200 J/TH
BM1373 (3nm, 2026): 2,500 GH/s, 10 J/TH
Improvement: 83× hashrate per chip, 20× efficiency, 11 years

For context: an Antminer S9 from 2017 needed 189 chips to deliver 14 TH/s. The Antminer S23 needs ~127 BM1373 chips to deliver 318 TH/s — 23× the hashrate from 67% the chip count, on a single device that fits in a similar form factor. That's what a decade of silicon evolution looks like in practical terms.

The chips, one by one

BM1385 (2015) — the patriarch

The first Bitmain chip widely deployed at scale. Built on TSMC's 28nm process. The Antminer S7 used 162 of these chips to deliver 4.7 TH/s at 1,293W — efficiency around 275 J/TH at the wall, ~200 J/TH at the chip level. By 2026 standards, the S7 produces less hashrate than a single Bitaxe Gamma chip. By 2015 standards, it was state of the art.

BM1387 (2017) — the legend

The chip that won Bitcoin mining for half a decade. The Antminer S9 used 189 BM1387 chips to deliver 14 TH/s at 1,372W (~98 J/TH). For years, the S9 was the most-deployed Bitcoin miner on the planet — millions of units shipped. Even today (2026), some S9s are still profitable in regions with sub-$0.04/kWh power. Eight years of useful service from a single chip generation. No other Bitmain chip has matched that longevity.

BM1397 (2019) — the 7nm pivot

First mainstream 7nm chip from Bitmain. Used in Antminer S17 series. Roughly halved the J/TH from the BM1387 era. Also became the basis for the original Bitaxe MAX project — the first DIY single-chip solo miner. The BM1397 used pre-calculated midstates rather than receiving full block headers, an architectural detail that distinguished it from later generations.

BM1366 (2022) — the 5nm jump

The first 5nm chip in Bitmain's mining lineup. Massive efficiency leap to ~21 J/TH. Used in Antminer S19 XP (140 TH/s, 21.5 J/TH) and the Bitaxe Ultra. The Bitaxe Ultra holds a special place in solo mining history — in March 2025, a single Bitaxe Ultra at ~0.48 TH/s solved Bitcoin block #887,212, paying out 3.125 BTC after submitting 619 million shares. The most-cited example of "lottery mining actually paying off" in the modern era.

BM1368 (2024) — the architecture redesign

This is where it gets interesting. The BM1368 was the first chip in a generation that made deep architectural changes — not just a process shrink. Two key changes:

• Voltage domain redesign: The BM1368 moved from the traditional ~0.4V domain to ~1.0-1.2V. This sounds backwards — higher voltage usually means more power — but coupled with the new architecture it allowed simpler power delivery, fewer voltage regulators, and substantially higher per-chip hashrate.
• Eliminated the PIC controller: Previous-generation Bitmain chips relied on a separate PIC microcontroller to manage voltage scaling and chip communication. The BM1368 integrated these functions directly. Result: simpler hashboards, fewer points of failure, easier firmware development.

The Antminer S21 used 108 BM1368 chips to deliver 200 TH/s at 17.5 J/TH. The Bitaxe Supra used a single BM1368 to deliver 600-750 GH/s at ~22 J/TH on the desktop. The architecture redesign delivered roughly 6-7× per-chip hashrate over the BM1366 generation — the biggest single-generation jump in Bitmain history.

BM1370 (2024-2025) — the refinement

The BM1370 took the BM1368 architecture and pushed it harder. Same 5nm process but refined for higher per-chip hashrate (~1.2 TH/s vs 0.7) and better efficiency (~15 J/TH vs 17.5). Used in:

• Antminer S21 Pro — 195 chips × 1.2 TH/s = 234 TH/s at 15 J/TH (~3,510W)
• Antminer S21 XP Hyd — 324 chips × 1.46 TH/s = 473 TH/s at 12 J/TH hydro-cooled (~5,676W)
• Bitaxe Gamma — 1 chip, 1.0-1.2 TH/s stock, up to 1.84 TH/s overclocked at 900 MHz / 1250 mV
• NerdQAxe++ / Zyber 8G — 4 chips, 4.8+ TH/s
• NerdOCTAxe — 8 chips, 10-12 TH/s

The BM1370's wide voltage window (0.65V to 1.30V) and frequency headroom (525 MHz stock, up to 900-1000 MHz overclocked on good silicon) made it a community favorite. Bitaxe overclocking guides sprouted everywhere. AxeOS firmware added voltage/frequency tuning UIs. The chip became the bridge between industrial-grade silicon and DIY desktop mining culture.

BM1373 (2026) — the 3nm future

Bitmain's first 3nm SHA-256 chip. Per-chip specs:

• ~2.5 TH/s per chip — roughly double the BM1370
• ~25W per chip — slightly higher than BM1370 (which is ~17W stock)
• 10 J/TH efficiency — 33% better than BM1370
• 3nm process — first node shrink for Bitmain in 4 years

Deployed across the Antminer S23 series:

The S23 Hyd 3U is genuinely remarkable: 1.16 PH/s in a single rack-mount unit, drawing 11kW on 380-415V three-phase power. A single S23 Hyd 3U produces more hashrate than the entire 4× S21+ fleet that SoloFury operates today. Bitmain quotes a 7-year warranty on these units, signaling confidence in the silicon's longevity.

The Bitaxe and NerdQAxe community is already adapting boards for the BM1373. TinyChipHub (the de facto open-hardware ASIC supplier) ships sealed reels of BM1373 chips, and 4-chip NerdQAxe++ builds are projected to deliver 10-12 TH/s — directly matching the Zyber 8G Solo Miner's hashrate but at significantly lower J/TH. The desktop solo mining ceiling just moved up another order of magnitude.

The competition: MicroBT (Whatsminer)

MicroBT is Bitmain's most serious competitor in the SHA-256 space. They design their own ASIC chips (not licensed from Bitmain) and have built a parallel evolution path:

MicroBT's strategy has been steady refinement rather than dramatic architecture jumps. Their M60 series uses 5nm chips and competes directly with Bitmain's S21 lineup. Per-watt efficiency is roughly 10-15% behind the BM1370 generation — close enough that Whatsminer remains popular in markets where Bitmain availability is constrained (parts of Asia, Russia, certain African operations).

MicroBT has not yet announced a 3nm chip equivalent to the BM1373. Industry analysts expect a Whatsminer M70-series in late 2026 or 2027 to close the gap. Until then, the BM1373 / S23 series gives Bitmain a real efficiency lead at the top end.

The wildcard: Auradine

Auradine is a US-based ASIC startup that publicly announced the first Western-designed 3nm Bitcoin mining chip — the AT2880 Teraflux — at Bitcoin 2024 in Nashville. Specs (verified at deployment):

• Process: 3nm (the same node as BM1373)
• Per-chip hashrate: not officially published, but device-level efficiency comparable to BM1370 / BM1373 generation
• Used in their Teraflux mining unit (~100-200 TH/s per device, ~13-15 J/TH)
• Made-in-USA narrative: appealing to North American institutional buyers concerned about supply chain politics

Auradine isn't a high-volume player yet — their production run is small relative to Bitmain or MicroBT — but they represent the first genuine Western challenger to the Chinese mining ASIC duopoly. If geopolitical pressure on Chinese chip exports intensifies through 2026-2027, Auradine could grow significantly. Their silicon is competitive on paper. The question is manufacturing scale.

Architecture deep dive: what changed between BM1368 and BM1370

For miners who actually open their hardware, the BM1368→BM1370 transition is the most interesting engineering change in recent Bitmain history. Both chips use the same 5nm process node. Same logical architecture. Same SHA-256 cores. Yet the BM1370 delivers ~70% more hashrate per chip with similar power draw.

How? Three things:

1. More cores per die — refined 5nm cell library allowed denser SHA-256 core placement. Roughly 1.5× core count on similar die area.
2. Optimized power delivery — the BM1370's wider voltage window (0.65V to 1.30V) lets the chip dynamically scale between low-power steady-state and high-power burst modes. The BM1368 had a narrower window.
3. Better thermal coupling — chip package improvements (different solder ball pitch, better thermal interface to the heatsink) allowed sustained operation at higher clock speeds without thermal throttling.

For Bitaxe overclockers, this means BM1370 chips can be pushed to 900+ MHz on stock voltage — frequencies that would melt a BM1368 within minutes. It's not magic; it's metallurgy and packaging. Same silicon, smarter delivery.

What BM1373's 3nm jump actually delivers

The BM1373 is the first Bitmain chip to leave the 5nm node. The leap to 3nm produces:

• ~33% efficiency improvement at the chip level (15 → 10 J/TH)
• ~2× per-chip hashrate (1.2 → 2.5 TH/s)
• ~50% reduction in chip count for equivalent device hashrate
• Lower thermal density — even at higher per-chip power, smaller die means heat is easier to extract

The Antminer S23 Hyd at 580 TH/s, 9.5 J/TH represents what's currently possible with widely-deployed 3nm SHA-256 silicon. For comparison, the previous-generation S21 XP Hyd needed 12 J/TH for 473 TH/s. Same hydro cooling envelope. The 3nm node delivered 22% more hashrate at 21% better efficiency — both axes simultaneously. That's a genuine generational leap, not a marketing refresh.

What does this mean for solo miners? Two things:

1. Older hardware (S19 series, M30 series) is rapidly approaching obsolescence for any miner paying retail electricity rates. The efficiency gap is now too wide. By late 2026, expect significant fleet retirements.
2. The desktop solo mining ceiling moves up. Bitaxe-class single-chip BM1373 builds will deliver 2.5 TH/s in a desktop form factor. NerdQAxe-class 4-chip builds will deliver 10+ TH/s. This is the new floor for "consumer-scale" SHA-256 silicon.

The economic picture: chip generation and ROI

For miners running a fleet, the question isn't "is this chip cool?" — it's "does this chip pay for itself before the next generation makes it obsolete?"

Rough ROI math at $0.07/kWh hosting and current BTC price (~$96k):

Numbers are illustrative — real ROI depends on hashprice, difficulty, BTC price, and uptime — but the directional message is clear. The S23 series resets the ROI table. Older S19 hardware is now thermally and economically obsolete in most jurisdictions. S21 and S21+ remain profitable but with longer payback. The S23 Hyd is the new fleet flagship, and operators who wait too long to upgrade will be priced out of difficulty increases.

Implications for solo mining (and SoloFury)

For solo miners specifically, the chip evolution has three direct consequences:

1. Bitaxe-class hardware is the most viable it has ever been

A BM1373-based single-chip miner at 2.5 TH/s changes the math significantly. For BC2 / BCH2 chains where a single BM1370 Bitaxe finds blocks every 1-2 days, a BM1373 unit will find them in hours. For XEC, the expected time drops from ~50 days to ~25 days on a single chip. Solo mining at consumer scale is genuinely returning to viability, not just lottery mode.

2. Industrial S21+ fleets remain the BCH sweet spot — for now

SoloFury's 4× S21+ fleet (940 TH/s total) finds BCH blocks at a rate of roughly 1 per 22 days on average. That math holds regardless of generation, until the BCH network hashrate rises significantly (which would require S21+/S23 deployments at scale on BCH specifically — currently not happening). For 2026-2027, a small S21+ fleet remains the most cost-effective entry point for individual BCH solo miners.

3. The competitive pressure is real

Bitcoin's network hashrate will rise as S23 deployments scale. Operators on older hardware will be forced to choose: upgrade, find subsidized power, or shut down. Solo miners on smaller chains (BCH, BC2, BCH2, XEC) are insulated from this pressure because those networks aren't experiencing aggressive S23 deployment. The smaller chains remain solo mining's structurally protected niche.

What comes after BM1373

The gufo's predictions for 2027-2028:

• 2nm BM1xxx — Bitmain's next node shrink. Expect 4-5 J/TH at the chip level, roughly 50% better than BM1373. Devices likely deployable in late 2027.
• Vertical/3D stacking — the industry has been experimenting with stacked chip dies for memory. Mining ASICs may follow. This could deliver 2-3× per-chip hashrate without further node shrinks.
• Power delivery innovations — direct-on-chip DC-DC converters, integrated cooling channels, more aggressive voltage scaling. Architecture wins matter as much as process node wins now.
• End of "trivial" gains — process shrinks below 2nm get prohibitively expensive. Future efficiency improvements will increasingly come from architecture, not lithography. Innovation slows but doesn't stop.

The kicker

A decade of Bitcoin mining silicon has produced a 20× efficiency improvement and an 83× per-chip hashrate increase. The chips are smaller, faster, cheaper per unit work, and increasingly ubiquitous. The same algorithm. The same network. The same Satoshi whitepaper. Just better silicon, year after year.

For solo miners, this is good news and bad news. Bad news: the network gets harder every year, and small operators must upgrade or accept smaller relative shares. Good news: your Bitaxe Gamma at home has the same per-hash probability as a BM1373 in an industrial farm. The chip doesn't know it's small. The network doesn't care. Probability is uniform across hash count, regardless of who computed it.

The BM1373 is where Bitcoin mining sits in 2026: 3nm silicon, 10 J/TH, 2.5 TH/s per chip, deployed in machines that range from desktop NerdQAxe builds to rack-mount 3U behemoths consuming 11kW each. Eleven years from BM1385's 200 J/TH to BM1373's 10 J/TH. The next eleven years will probably bring another 5-10× improvement. The chips will keep shrinking. The network will keep adjusting. The math will keep working.

Pick your silicon. Pick your chain. Plug in. Wait. The dice are still rolling.

Every chip is a small miracle of physics: billions of transistors switching billions of times per second, computing one specific cryptographic puzzle in pursuit of a single number that will, eventually, with patience and luck, unlock a block. The owl knows: the silicon evolves, but the hunt remains the same.