Apple Watch Series 12 and Apple Watch Ultra 4 both ship with the S11, a chip Apple describes as its most powerful wearable chip yet and the first new Apple Watch chip family since the S9 arrived in 2023. Apple Watch Series 12 and Apple Watch Ultra 4 reach stores Friday, September 18.
Most of what has been written about the S11 describes what it enables: Audio Intelligence, Siri AI, faster background health sampling. Fewer sources describe the chip as hardware, so this piece sets aside the feature list and looks only at what Apple’s specs pages state about the silicon itself, including the figures that carried over unchanged.
The key numbers
| Item | Value |
|---|---|
| Chip | S11, 64-bit dual-core processor |
| Neural Engine | 4-core |
| Storage | 64GB |
| Security feature | Secure Exclave, a hardware-isolated compartment for on-device audio processing |
| Used in | Both Series 12 and Ultra 4 |
Three generations on one chip, then a new one
Apple’s own tech specs pages show the S10 chip powering Series 10 in 2024, then Series 11, Apple Watch SE 3 and Ultra 3 in 2025, three straight product generations sharing one chip design. The S11 breaks that run for Series 12 and Ultra 4 this year. That makes 2026 the first time since the S9’s debut in Series 9 that Apple has moved its watch line to a new chip family, rather than extending the previous one to another product. Apple Watch SE 3 also runs the S10 chip, per its own tech specs page, and Apple’s Series 12 and Ultra 4 announcements do not mention an S11 version of the SE line, so whether Apple’s entry-level watch moves to the new chip is not something Apple has stated either way this year.
Don’t miss the best of The Mac Observer
Set us as a preferred source and our Apple reporting ranks higher in your Google Search results and Discover feed — one tap, no account changes.
What the Secure Exclave adds, as a piece of silicon
Apple describes the S11 as including a Secure Exclave, which it calls a hardware-isolated compartment used for on-device audio processing, with immediate deletion of what passes through it. The distinction Apple draws is architectural: this is a boundary built into the chip itself, not a setting or a software permission that could be toggled off. It is the part of the S11 that Apple’s Audio Intelligence features, Sound Recognition, Live Rewind, Siri Recap and Shazam-style detection, run on top of, though Apple’s own description of the Secure Exclave is limited to what it isolates and does not extend to how large the compartment is or how it is fabricated.
The figures that did not move
| Spec | S9 / S10 generation | S11 (2026) |
|---|---|---|
| Neural Engine cores | 4-core | 4-core |
| Storage | 64GB | 64GB |
| CPU architecture | 64-bit dual-core | 64-bit dual-core |
Apple’s Series 9, Ultra 2, Series 10 and Series 11 tech specs all list a 4-core Neural Engine and 64GB of storage, and Apple’s Series 12 and Ultra 4 specs list the same two figures for the S11. A new chip family arriving with the same publicly stated core count and the same storage ceiling as its predecessor is not something Apple calls out directly. It means the S11’s advertised advances, on Apple’s own pages, sit in efficiency, the always-on processor and the new Secure Exclave, rather than in the core counts Apple chooses to publish.
What Apple has not said
Apple has not published a transistor count, manufacturing process node, clock speed or die size for the S11, figures it also withholds for every previous Apple Watch chip. It has not stated how much faster the S11’s CPU or GPU are compared with the S10 in any benchmark Apple names, and it has not described the physical size or location of the Secure Exclave within the chip package. Those gaps mean any performance comparison beyond what Apple states about specific features is not something this article, or Apple’s own pages, can support yet.
Apple Watch Series 12 and Ultra 4 are both available to pre-order now and reach stores Friday, September 18, running watchOS 27 out of the box.
