The Apple Watch Series 12 features the new S11 chip, which includes a secure enclave for microphone data processing, along with upgraded CPU, GPU, and Neural Engine components. The device also introduces a redesigned health sensor array with larger EKG electrodes and more efficient optical LEDs, enabling more frequent and accurate measurements.
A key capability of the new hardware is continuous heart rate monitoring, which now samples data every five seconds instead of every five minutes. Testing showed the device remained within five beats per minute of a Polar H10 chest strap. The watch maintains a 24-hour battery life, with a 20-minute charge increasing capacity from 20 to 64 percent.
The Series 12 introduces a readiness score, calculated on a scale of 0 to 10 based on sleep, activity, and a new recovery heart rate variability metric. This score requires seven nights of sleep to calibrate. The feature is exclusive to the Series 12 and Ultra 4 models due to the updated sensor requirements.
The S11 chip also powers new ambient listening features under the Audio Intelligence suite. While features like Live Rewind and Siri Recap are scheduled for a later software update, the watch currently supports faster Shazam music identification and sound recognition for alerts, such as alarms or sirens, which require manual activation.
