The S8 chip in the Apple Watch Series 8, Apple Watch Ultra and the second-generation Apple Watch SE has the same CPU as the S6 and S7 chips, as the identifiers show.
The CPU in Apple's S8 SiP carries the same identifier T8301 like the CPU in the S6 and S7 chips introduced in the Apple Watch Series 6 and Apple Watch Series 7. This explains why Apple has only compared its S-series chips to the S5 chip or earlier in recent years. This also means that the Apple Watch Series 6, Apple Watch Series 7, Apple Watch Series 8, Apple Watch Ultra, and the second-generation Apple Watch SE all come with the exact same processor.
New Apple Watch generation: The chip remains the same
Apple may have redesigned other parts of the SiP to accommodate new components, such as the new accelerometer and gyroscope found on the Apple Watch Series 8. The S6, S7, and S8 chips all feature 32GB of storage and dual-core CPUs. When Apple last revealed the S6 in the Apple Watch Series 6, the last time Apple gave performance details on its latest smartwatch lineup, it said the chip makes app launches 20 percent faster. The S6, S7, and S8 are based on Apple's A13 Bionic chip from the iPhone 11 and are manufactured using TSMC's 7nm process. With the A14 Bionic chip, Apple has switched to TSMC's 5nm process, and the iPhone 14 Pro's A16 Bionic is the first Apple chip to be manufactured using a 4nm process.
One explanation for Apple not advancing the CPU technology in the S-series chips is that using the cores from the A14 chip and TSMC's 5nm or 4nm processes would primarily result in performance improvements that are no longer necessary for the Apple Watch. Waiting for TSMC's 3nm process, which is due to enter mass production later this year, could lead to more significant efficiency improvements - an area that is much more important for the Apple Watch as it could increase battery life. (Image: Apple)
