The EETimes has published a review that reveals how Apple scales its processor architecture for different product lines.

All Apple Watch Series 9 models are equipped with the new S9 processor, but according to the latest analysis, this chip is not mass-produced on TSMC’s advanced “3nm N3B” process, which was also used to make the A17 Pro and M3 processor series. Instead, the watch’s chipset is actually based on Apple’s previous-generation 4nm A16 Bionic, which is found in the new iPhone 15 and iPhone 15 Plus. This all shows how flexible and scalable the tech giant’s chip architecture is.

The S9 processor in the Apple Watch Series 9 is a shortened version of the mobile A16 Bionic — Here we see how the experience in creating maps for scrolling shooters helps in creating processor cores.

A16 Bionic is equipped with two high-performance cores and four energy-saving cores. The chipset is also equipped with a five-core GPU. But, for the Watch Series 9, Apple has used fewer CPU and GPU cores, so the S9 has a dual-core processor along with a single GPU core. This means that the S9 won’t have the same power as the A16 Bionic, but that’s not necessary because the Apple Watch Series 9 is a completely different class of product compared to the iPhone 15 and iPhone 15 Plus. The analysis published by EETimes also shows that Apple widely uses scalable architecture in laptops, which allows for significant savings in development and production. Because each chipset that is created for one product can also be scaled up for use in another area.

For example, the analysis claims that the M3, M3 Pro, and M3 Max chips are based on the A17 Pro and have a larger crystal, although they are mass-produced using the 3nm process. Why does none of the Apple Watch Series 9 models have a 3nm chip? This is likely due to the extremely high costs associated with manufacturing this silicon. The estimated cost of setting up production of M3, M3 Pro, and M3 Max chips is $1 billion. It may not make sense to use an advanced manufacturing process for the Apple Watch Series 9. We hope that the S10 chip, which will debut with the Apple Watch Series 10, will be produced on TSMC’s new “3nm N3E” line.