When iFixit tore down the Apple Watch last week, one of the things it couldn't dig into was the S1 "System in Package" (SiP) that powers the device. The S1's components were covered in a "solid block of plasticky resin" rather than a standard heat spreader, so we couldn't see the individual chips and controllers on the board like we usually can in iFixit teardowns.

Today ABI Research took things one step further, removing that block of resin and exposing what's underneath. Most of the components aren't surprising. There's a Broadcom BCM43342 chip for dual-band 802.11n Wi-Fi and Bluetooth 4.0, 512MB of RAM from Elpida, and 8GB of flash memory from Sandisk and Toshiba. An NFC controller from NXP and a signal booster from AMS enable Apple Pay on the watch, and interestingly these appear to be identical to the NFC components inside the iPhone 6 and 6 Plus. Other chips include a combination accelerometer and gyroscope from STM and a touchscreen controller from ADI.

The most interesting component under the hood is the custom Apple CPU and GPU at the center of it all, here identified only as APL 0778. We still don't know what CPU architecture powers this chip, what its manufacturing process is, or how fast it is relative to the A-series SoCs that power iPhones and iPads—we'll need to wait on more detailed analysis from the likes of Chipworks for more insight. That said, developer Steve Troughton-Smith has already dug into the watch's software and discovered a driver for the PowerVR SGX543 GPU, the same basic architecture found in the Apple A5. That GPU is included in the iPad 2, iPhone 4S, iPad Mini, fifth-gen iPod Touch, and (in a special version with one CPU core) the third-generation Apple TV.

We'll continue to post as we get more information about the inner workings of the S1.

Update: Chipworks has done some additional work on the S1 and has given us some scraps about the APL 0778 CPU and GPU at the heart of it all. It's a 5.2mm by 6.2mm chip and it's manufactured on Samsung's 28nm LP process. 28nm is a node away from being cutting-edge at this point (Samsung has a new 14nm process and we're just seeing the first chips built on it in phones like the Galaxy S6), so it's interesting to find it here—if Apple goes with a newer process in next-generation Apple Watch hardware, it should actually have a fair bit of headroom to reduce power consumption, improve performance, reduce the amount of physical space the chip needs, or some combination of all three.