Apple Watch Series 12 and Apple Watch Ultra 4 models may contain twice as much physical flash storage as their official specifications suggest. A Chinese hardware researcher claims the watches use a 128GB NAND flash die, even though both models are listed as offering 64GB of storage.

The finding has not established how much of that physical capacity is available to users or why Apple would restrict access to it. Teardowns could provide more information about the components inside the new watches and how their storage is configured.

What the storage discovery shows

A 128GB NAND storage profile associated with the T8320 chip used in the Apple Watch Series 12 and Ultra 4 was identified earlier this month, according to the researcher. That profile suggests the watches may include a 128GB flash component rather than a 64GB part.

However, the discovery does not prove that the watches can access the full capacity. Apple’s official storage figure for both models remains 64GB, so some of the physical flash could be reserved or otherwise unavailable to the operating system.

Why Apple might reserve the extra capacity

The reason for the apparent difference is unclear. One possibility is that Apple has set aside part of the flash for intensive sensor-related read and write activity. A reserved portion could also act as a durability buffer, potentially giving the storage additional spare capacity as individual memory cells wear over time.

Those explanations remain possibilities rather than confirmed details. The available information does not indicate whether the unused capacity is allocated to a specific feature, hidden from users for technical reasons, or simply part of a component choice that gives Apple additional flexibility during manufacturing.

A similar example from the iPad Pro

Apple has previously used more physical memory than the amount made available to a device’s system. Teardowns of the 2024 M4 iPad Pro indicated that models advertised with 8GB of RAM contained 12GB of physical memory, with only 8GB accessible to the system.

That earlier example does not confirm the same approach for Apple Watch, but it shows how the capacity listed in a product specification can differ from the total amount present in the hardware.

Teardowns could confirm the configuration

The storage claim should be treated as unconfirmed until independent teardowns examine Apple Watch Series 12 and Ultra 4 hardware. A teardown could identify the NAND package directly and help determine whether the watches use a 128GB component with part of its capacity disabled or reserved.

For buyers, the immediate practical difference may be limited because Apple continues to present both models as 64GB devices. The discovery is more significant as a look at Apple’s component choices and how the company manages storage capacity inside compact wearable hardware.