Tesla's FSD Hardware 4.5: A 3-Chip Upgrade Before AI5?
January 23, 2026
By Karan Singh
The Big Reveal
Tesla is reportedly gearing up to release, or has already started using, a new HW 4.5 FSD computer in its vehicles. This upgrade, as indicated by the moniker, might seem like a minor revision, but it could be a significant leap in computing power. The discovery was made by an astute observer, Todd deRego, who spotted the new component listed in the official Tesla Electronic Parts Catalog.
The Findings
The part, CAR COMPUTER - LEFT HAND DRIVE - PROVISIONED - HARDWARE 4.5, is explicitly listed with the part number 2261336-S2-A and a price tag of $2,300.00. This pricing suggests it's intended as a replacement or upgrade rather than a new retrofit item.
The 3-SoC Theory
Longtime Tesla firmware hacker, Green, offers an intriguing insight. Tesla's firmware has long referenced a 3-SoC (System-on-Chip) design. Historically, Tesla's FSD computers (HW3 and HW4) have used a dual-SoC setup, providing redundancy. If HW4.5 is indeed a 3-SoC architecture, it opens up new possibilities.
Why 3?
The third node's purpose is unclear, but several benefits emerge. Raw throughput is enhanced, enabling larger, more complex inference models. As FSD models grow exponentially in size, they demand more memory and compute. A 3-SoC setup allows Tesla to split the load, running larger neural networks that would otherwise strain the HW4 unit.
Additionally, the 3-SoC design introduces Triple Modular Redundancy (TMR). If one chip misinterprets an obstacle, the system can 'vote' to ignore the error, ensuring smooth driving. This fault tolerance adds an extra layer of safety.
A Bridge to AI5
With AI5, Tesla's next-gen FSD chip, set for production later in 2026 and full volume in 2027, a gap emerges. Software often outpaces hardware, and HW4.5 could be a stopgap until AI5 is ready. This upgrade ensures millions of cars aren't left behind as neural networks evolve.
Tesla's Autonomous Revolution
In a groundbreaking move, Tesla has launched unsupervised Robotaxi rides in Austin, Texas, marking a significant milestone in autonomous public transit. This shift from supervised to unsupervised rides is a bold step, and Tesla's strategy, relying on cameras and AI, sets it apart from competitors like Waymo and Zoox.
AI5: The Next Frontier
Elon Musk confirms AI5's arrival in late 2026, with high-volume production in 2027. This chip is pivotal for FSD's advancement, and Tesla's commitment to it is evident. The company is focusing on AI4-equipped Cybercabs this year, but the question of upgradeability to AI5 remains.
AI5's performance is compared to NVIDIA's H100, a powerful data center chip. Tesla claims to achieve similar inference capabilities in a compact, low-voltage package, making every future Tesla vehicle a supercomputer equivalent.
The Return of Dojo
With AI5's architecture finalized, Tesla's silicon design team is shifting focus to Dojo 3 (AI6), indicating the hardware for neural net training is ready.
