All Apple Watch Series 9 models are equipped with the new S9 SiP, but according to the latest analysis, this chip is not mass-produced using TSMC's most advanced 3-nanometer "N3B" process, which was also used to manufacture the A17Pro and M3 series. Instead, the smartwatch's "packaging system" is actually based on Apple's previous-generation A16 Bionic chip, which is also used in the new iPhone 15 and iPhone 15 Plus.
The fact that the S9 is based on the iPhone SoC reveals the scalability of the tech giant's chip architecture and is a cost-effective way to design chips for a variety of products.
A16Bionic offers two high-performance cores, compared to four energy-efficient cores found in larger products such as the iPhone. The chipset also sports a 5-core GPU, but it would be outrageous to believe that all of those cores could fit into the same size package as the S9. In contrast, Apple uses fewer CPU and GPU cores on the Apple Watch Series 9 SoC, and the S9 uses a dual-core processor and a single GPU core.
While this means the S9 won't perform as well as the A16 Bionic, it doesn't have to be because the Apple Watch Series 9 is in a completely different product category compared to the iPhone 15 and iPhone 15 Plus. The analysis report released by EETimes also shows that Apple adopts a scalable architecture, which allows it to save a lot of design, tape-out and production costs, because each chipset tailored for different products can also be expanded for more powerful products such as iPad Pro or Mac, and vice versa.
As for why none of Apple Watch Series 9 uses 3nm chips? This may be related to the extremely high cost of manufacturing such chips.
According to reports, the manufacturing cost of M3, M3 Pro and M3 Max is as high as US$1 billion, and Apple Watch Series 9 offers fewer functions and features than other product series, so using cutting-edge manufacturing processes on S9 makes little sense. Hopefully, with the debut of the S10 SiP and Apple Watch Series 10, we'll hear about TSMC's use of the new 3-nanometer "N3E" process to give the chips more advanced features.