Let's get this out of the way — it's going to be really hard to properly identify what Apple's doing withe S1 due to the amount of custom silicon they're doing these days, but it's still interesting to see the educated guesses that are surfacing about the heart of the Apple Watch. This time it's ABI Research, and what they found was surprisingly similar to the iPhone and iPad:

"The design is an obvious variation from Apple's smartphones, with many high-end functions / chips included that normally would not be found in a simple watch," comments Jim Mielke, VP Engineering at ABI Research and head of the TeardownIQ group.

Interestingly, the S1 seems to lack DRAM (dynamic random access memory), which is found in most computers, including Apple's own iPhone and iPad. Instead, the S1 utilizes 512MB of SRAM, or static random access memory.

Unlike Apple's custom A8 chip, which combines the CPU, GPU, and RAM onto a single die, the S1 packs in an entire computer system into a single, sealed package. These include the Wi-Fi, Bluetooth, and NFC radios and the 8GB of on-board storage.

ABI S1 teardown

Source: ABI Research

Apple Watch