S11 chip checks heart rate every 5 seconds, HRV sampled 24x more often, plus a Readiness Score and four Audio Intelligence features; Thai price 29,900 baht
The Apple Watch Ultra 4 comes with 3 main upgrades: more accurate heart measurement, longer battery life, and AI-powered audio features. The new health sensor system works with the S11 chip, measuring heart rate every 5 seconds throughout the day and sampling HRV 24x more often than the previous generation.
On battery, general use reaches up to 50 hours, low-power mode 84 hours, a 15-minute charge adds 18 hours, and Max Extended Workout mode lasts up to 45 hours (enough for a 100-mile ultramarathon). The 4 AI audio features — Sound Recognition, Live Rewind, Siri Recap, and Shazam — process on the S11 chip's Secure Exclave and delete audio immediately after use. The 49mm titanium case starts at 29,900 baht in Thailand, pre-orders September 10, US sales September 18; Thailand's sale date isn't confirmed yet.
Source: Apple
