ASIC Chip Comparison — Mining ASIC Reference

Overview

Bitmain's BM13xx family of SHA-256 mining ASICs has evolved rapidly over five generations, doubling energy efficiency from approximately 30 J/TH down to 15 J/TH in just four years. This page provides a side-by-side comparison of all current-generation chips and guidance on identification, selection, and sourcing for repair work.

Understanding which chip is in your miner — and how it differs from chips in other models — is essential for diagnostics, repair, and component sourcing. While all BM13xx chips share the same daisy-chain communication protocol and basic architectural concepts, they differ significantly in operating voltage, process node, pin configuration, and PLL encoding. Using the wrong replacement chip will not work and can damage the board.

Chip Comparison Table

Chip Evolution

The progression from BM1398 to BM1370 follows a clear trajectory of process shrinks and architectural optimization:

Generation 1: BM1398 (7nm, 2020)

The BM1398 launched with the Antminer S19 and S19 Pro, establishing Bitmain's 7nm mining ASIC platform. At approximately 30 J/TH, it was a major improvement over the previous 12nm and 16nm chips. The BM1398 defined the communication protocol, domain-based power architecture, and PLL configuration scheme that all subsequent BM13xx chips would inherit. With hundreds of thousands of units deployed, it remains the most commonly encountered chip in the repair market.

Generation 2: BM1362 (7nm Improved, 2021)

The BM1362 stayed on the 7nm process but incorporated layout optimizations and revised power delivery. Running at 0.32V with approximately 24.5 J/TH efficiency, it powered the cost-effective S19j Pro series. The BM1362 proved that significant efficiency gains were achievable through design refinement without requiring a process node change.

Generation 3: BM1366 (5nm, 2022)

The BM1366 marked Bitmain's transition to 5nm manufacturing. At 0.28V and approximately 21.5 J/TH, it enabled the Antminer S19 XP to deliver 140 TH/s — a significant hashrate increase alongside improved efficiency. The move to 5nm brought new challenges in power delivery (tighter voltage tolerance) and thermal management (higher power density per unit area).

Generation 4: BM1368 (5nm, 2023)

The BM1368 refined the 5nm platform for the Antminer S21 series. Operating at 0.30V with approximately 17.5 J/TH, it included additional hashing cores and an optimized PLL design. The S21's 156-chip, 12-domain board layout represented a new standard for Bitmain's board architecture.

Generation 5: BM1370 (5nm Advanced, 2024)

The BM1370 is the current state-of-the-art, pushing 5nm optimization to its limits. At 0.27V and approximately 15 J/TH, it operates at the lower boundary of reliable silicon performance. It powers the Antminer S21 Pro and S21 XP — the most efficient air-cooled Bitcoin miners available.

How to Choose Replacement Chips

Selecting the correct replacement chip is critical. There is no cross-compatibility between BM13xx models — you must use the exact same chip model that the board was designed for.

Step 1: Identify Your Miner Model

The miner model determines which chip is on the hashboard. Use the label on the miner chassis or the firmware's system information page:

Step 2: Verify on the Board

If the miner label is missing or you have a loose hashboard, verify the chip model by reading the markings on the chip itself (see Chip Identification below) or by checking the board's part number silkscreened on the PCB edge.

Step 3: Source Correctly

When sourcing replacement chips:

• New pulls (chips desoldered from scrapped boards) are the most common source. Quality varies — inspect solder balls for damage and verify the chip responds before final installation.
• Factory new chips are occasionally available from authorized distributors but are expensive and may have minimum order quantities.
• Reballed chips come with fresh solder balls applied. Verify the ball alloy matches your board's solder (leaded vs. lead-free) to avoid reliability issues from mixed-alloy joints.

Chip Identification

Reading Chip Markings

Bitmain ASIC chips have laser-etched markings on the top surface of the BGA package. The markings include:

• Model number — Printed prominently, e.g., "BM1398" or "BM1366". This is the primary identifier.
• Date code — A numeric or alphanumeric code indicating the manufacturing date. Format varies: YYWW (year + week) is common.
• Lot number — Identifies the manufacturing batch. Useful for tracing systematic defects.
• Bitmain logo or branding — Some generations include the Bitmain name or a logo mark.

Visual Identification

When markings are worn or illegible (common on chips that have been reflowed), you can identify the chip by:

Distinguishing 7nm from 5nm Chips

The 7nm chips (BM1398, BM1362) and 5nm chips (BM1366, BM1368, BM1370) differ in their operating requirements:

Board-Level Differences

Beyond the chip itself, hashboards designed for different chips have fundamentally different:

• Voltage regulator ratings — 5nm boards use lower-voltage, higher-current regulators
• Domain structure — Chip count per domain varies (2 for S19, 13 for S21)
• PCB layer count and trace geometry — Power distribution networks are redesigned for each generation
• Thermal interface — Newer boards use improved TIM and heatsink designs for the higher power density of 5nm chips
• Control board interface — While the protocol is similar, firmware must be matched to the chip model

Efficiency Progression

The efficiency improvement across generations follows a clear curve of diminishing returns, as each successive process optimization yields smaller absolute gains:

Each generation roughly halves the gap to the theoretical minimum energy per hash, meaning future gains will be increasingly difficult to achieve without fundamental changes in hashing architecture or semiconductor technology.

Common Questions

Can I upgrade my S19 to use BM1366 chips?

No. The board layout, voltage regulators, domain structure, and control firmware are all specific to the chip model. Upgrading chips requires a completely new hashboard designed for the target chip.

Are BM1362 and BM1398 interchangeable?

No. Despite both being 7nm, they have different ball maps and PLL register encodings. They are not drop-in replacements for each other.

Which chip is easiest to repair?

The BM1398 has the largest market for replacement components, the most forgiving voltage tolerances, and the most documented repair procedures. It is the best chip for technicians learning BGA rework.

How do I know if a chip is counterfeit?

Inspect markings under magnification for consistency — counterfeit chips often have uneven laser engraving, incorrect fonts, or markings that smear when cleaned with IPA. Verify the chip functions by enumerating it on a known-good board before installing in a customer unit.

Further Reading

• ASIC Chip Architecture
• Voltage Domains & Regulators
• Clock Distribution & PLL
• BGA Rework Guide
• Cooling & Thermal Management