GoKawiil
Tech News
After several days testing the Apple Watch Series 12, a reviewer highlights the new S11 chip as a major speed boost, especially noting Siri now runs smoothly under watchOS 27. The device also gains new health complications—Heart Rate, Daily Steps, and Readiness—thanks to an updated Health Sensing System, plus quicker charging that delivers up to 12 hours of battery from just 15 minutes on the charger.
Apple's new Watch Series 12 and Ultra 4 use a Health Sensing System that samples heart rate every five seconds instead of every five minutes, requiring the optical sensor's green light to flash almost continuously. To avoid that light being visible in dark settings, Theater Mode automatically slows heart rate readings back to five-minute intervals, but a new setting lets users override this and keep continuous measurements.
Apple's Series 12 smartwatch introduces a single-tap hand gesture for navigating Smart Stack widgets alongside existing double-tap and wrist-flick controls. It also debuts a new Health Sensing System with 32 ECG electrodes, ring-arranged photodiodes, and larger LEDs, enabling heart rate readings every five seconds and HRV readings every five minutes, up from every five minutes and two hours respectively on Series 11. The new S11 chip also improves step-tracking accuracy and adds a real-time Steps complication to the watch face.
Apple's latest Watch Series 12 and Ultra 4 keep familiar shapes but introduce a new underlying Health Sensing System aimed at improving health tracking accuracy. The Series 12 gets a roughly 2% smaller display area, a slightly wider case, Ceramic Shield 2 glass on aluminum models, and four new aluminum finishes including Dark Bronze and Light Gold. Ultra 4 retains its titanium build in Natural and Black finishes.
Apple Watch Series 12 keeps the same 42mm and 46mm display sizes as Series 10 and 11, but its case width has grown by about 1mm, which Apple did not mention at launch. That extra case size without a corresponding display increase means the new watch has noticeably thicker bezels than its predecessors.
Apple's marketing materials for the Apple Watch Series 12 and Ultra 4 reveal that the small circular Heart Rate complication, previously just an app-launcher icon, will now display an actual live heart rate number. This upgrade is enabled by the new Health Sensing System, which measures heart rate every five seconds—60 times more often than earlier Apple Watch models. The feature does not appear on watchOS 27's release candidate for the older Series 11 and Ultra 3, suggesting it's tied to new hardware.
Apple's new Ultra 4 keeps the same design as Ultra 3 but adds a new S11 chip, doubles RAM to 4GB, and introduces a redesigned Health Sensing System with upgraded heart rate and HRV tracking. New features include high-frequency background heart rate monitoring, a heart rate watch face complication, more frequent HRV readings, a new Recovery HRV metric, and more accurate real-time step tracking.
Apple published a detailed study comparing the heart rate sensing of its new Health Sensing System in Apple Watch Series 12 and Ultra 4 against rivals like Garmin, Google Pixel Watch, Huawei, Samsung, WHOOP, and Oura Ring. The test involved over 1,400 participants across five sites in the US and Malaysia, using a Polar H10 chest strap as the accuracy benchmark during activities like running, cycling, HIIT, and daily tasks.