Xiaomi Watch S4 Smartwatch In-Depth Performance Review & Benchmark

The Definitive Xiaomi Watch S4 Smartwatch Review: A New Benchmark in Premium Wearable Technology

Introduction: The Convergence of Classic Horology and Cutting-Edge Tech

The smartwatch industry has reached a fascinating inflection point. The initial novelty of wrist-based notifications and basic step counting has given way to a mature market where consumers demand not just functionality, but a seamless integration of sophisticated technology, robust health monitoring, and timeless design. The line between a “gadget” and a “timepiece” is blurring, and in this new era, Xiaomi has emerged as a formidable force, consistently challenging the status quo by democratizing premium features. With the launch of the Xiaomi Watch S4 Smartwatch, the brand is not just participating in the premium market; it is aiming to redefine it. The Watch S4 arrives as a bold statement, a culmination of years of engineering prowess, promising a harmonious blend of classic watchmaking aesthetics and next-generation smart capabilities. On paper, it is a technological tour de force: a vibrant 1.43-inch OLED display, an innovative interchangeable bezel system that merges hardware and software, intuitive gesture controls for one-handed operation, a marathon 15-day battery life, and the fluid, efficient experience of Xiaomi’s new HyperOS. This feature set places it in direct competition with the industry’s most established and expensive players. But does the real-world experience live up to this extraordinary promise? This is not a cursory glance at a new product. This is an exhaustive, technical deep-dive into every facet of the Xiaomi Watch S4. We will meticulously analyze the performance and quality of its high-refresh-rate OLED display. We will deconstruct the ingenious mechanism of its interchangeable bezel and the unprecedented level of customization it offers. We will put its gesture controls, advanced sensor suite, and multi-system GNSS to the test in real-world scenarios. We will scrutinize its battery claims and explore the nuances of its HyperOS software and Alexa integration. Our mission is to provide an unparalleled level of detail to answer the critical questions: Is the Xiaomi Watch S4 a true flagship killer? Where do its strengths lie, and what are the necessary trade-offs? And ultimately, does it represent the new benchmark for what a premium, intelligent timepiece should be in the modern age? If you are a discerning tech enthusiast, a fitness aficionado, or a style-conscious individual seeking the pinnacle of wearable technology, join us as we embark on this definitive exploration of the Xiaomi Watch S4 Smartwatch.

A Masterclass in Design and Display Technology

The first and most immediate interaction with any smartwatch is its physical presence and its display. It is the component that defines the device’s character, dictates its usability, and serves as the window into its digital soul. With the Watch S4, Xiaomi has clearly prioritized these elements, delivering a design and display package that is not just functional, but genuinely luxurious and technologically advanced.

The Visual Centerpiece: A 1.43-inch High-Refresh-Rate OLED Display

The Xiaomi Watch S4 Smartwatch is graced with a stunning 1.43-inch circular OLED display, a technology that represents the pinnacle of current screen technology for wearables. Unlike traditional LCD screens that require a constant backlight, each of the pixels in an OLED (Organic Light Emitting Diode) display is its own individual light source. This fundamental difference yields a visual experience that is simply on another level. The most significant advantage is the ability to achieve true, absolute blacks. When a pixel needs to be black, it simply turns off completely, consuming no power. This results in what is effectively an infinite contrast ratio. The inky, deep blacks make every other color on the screen pop with incredible vibrancy and saturation. Watch faces with intricate details and rich colors appear almost painted onto the glass, and text is exceptionally legible against the dark background. This contrast is not just an aesthetic luxury; it also dramatically improves readability in all lighting conditions, from a dimly lit room to the brightest direct sunlight. The technical specifications of the display are equally impressive. The resolution is a crisp 466 x 466 pixels, which, on a 1.43-inch panel, translates to a pixel density of 326 PPI (Pixels Per Inch). This is a crucial metric, as it determines the sharpness and clarity of the image. At 326 PPI, the display is incredibly sharp, rendering text without any jagged edges and displaying fine details in icons and watch face complications with perfect clarity. It’s a “retina-grade” experience where individual pixels are imperceptible to the naked eye. Another key feature is the 60Hz refresh rate. Many smartwatches, especially in the mid-range, operate at a lower 30Hz refresh rate to conserve power. The 60Hz refresh rate on the Watch S4 means the screen updates 60 times per second, resulting in animations, scrolling through menus, and transitions that are exceptionally smooth and fluid. This buttery-smooth performance significantly enhances the premium feel of the device, making every interaction feel responsive and instantaneous. The power efficiency of the OLED panel also enables a robust Always-On Display (AOD) feature. The watch can display a simplified, low-power version of the watch face continuously, allowing you to glance at the time just as you would with a traditional timepiece, without the need for a wrist flick or a screen tap. This small but crucial feature elevates the S4 from a reactive gadget to a proactive, ever-present watch.

A Fusion of Form and Function: The Innovative Interchangeable Bezel

Perhaps the most groundbreaking and unique design feature of the Xiaomi Watch S4 is its interchangeable bezel system. This is a brilliant fusion of hardware and software that draws inspiration from the world of traditional luxury watchmaking, offering a level of personalization and tactile satisfaction that is virtually unprecedented in the smartwatch space. The system is more than just a cosmetic accessory; it is an integrated experience. The watch is designed with a removable outer bezel that can be easily twisted off and replaced with a different one. Xiaomi offers a variety of bezels with different finishes, colors, and textures (such as a classic toothed diver-style bezel or a sleek, polished one), allowing you to dramatically alter the physical appearance of the watch to suit your style or the occasion. The true genius of this system, however, lies in its intelligent integration with the software. When you install a new, official dress-up bezel, the watch detects the specific bezel and automatically switches to a dedicated, matching watch face, often accompanied by a satisfying sound effect. This creates a cohesive and deeply satisfying user experience, where the physical hardware and the digital interface feel perfectly in sync. It feels less like changing a setting and more like transforming the watch itself. This feature elevates the Watch S4 from a static piece of technology to a dynamic fashion accessory. You can have a rugged, sporty look for the gym, a sophisticated, classic look for a business meeting, and a minimalist, modern look for a casual weekend, all with the same core device. This nod to the heritage of traditional horology, where bezels serve both functional and aesthetic purposes, is a masterful touch that will appeal to watch enthusiasts and tech lovers alike. The bezel is not just for show; it is also seamlessly integrated and provides a protective raised edge around the display, helping to shield the screen from accidental bumps and scratches, a perfect marriage of form and function.

Next-Generation Interaction and Performance

A beautiful design is only as good as the user experience it houses. The Xiaomi Watch S4 is powered by the new, efficient Xiaomi HyperOS and introduces innovative ways to interact with the device, pushing the boundaries of what we expect from a smartwatch.

The Power of a Flick: Quick Gesture Control

One of the most futuristic and genuinely useful features of the Xiaomi Watch S4 Smartwatch is its advanced gesture control system. This technology leverages the watch’s sophisticated motion sensors (the accelerometer and gyroscope) to allow you to perform key actions with simple, intuitive wrist movements, enabling true one-handed operation. This is a significant step forward in making smartwatch interactions more seamless and accessible, especially in situations where your other hand is occupied. The system is designed to recognize specific, deliberate movements. For example, a quick twist or flick of your wrist can be customized to trigger a variety of functions. Imagine you’re carrying groceries and a call comes in. Instead of fumbling to tap the screen, a simple flick of your wrist can be configured to reject the call. You can customize these gestures within the settings to link to other useful actions, such as: activating the built-in Alexa voice assistant to ask a question or set a reminder, waking the screen to check the weather information, or even acting as a remote shutter to take a photo on your connected smartphone. The responsiveness and accuracy of these gestures are key to their utility, and Xiaomi’s advanced sensor fusion algorithms ensure that the watch can reliably distinguish between a deliberate gesture and an accidental arm movement. This technology represents a move towards a more ambient and intuitive form of computing, where the device adapts to your natural movements rather than requiring your constant, focused attention. It’s a subtle but powerful innovation that, once you get used to it, is hard to live without.

Fluid and Efficient: The Xiaomi HyperOS Experience

Powering the entire experience is Xiaomi HyperOS, a proprietary operating system designed from the ground up for efficiency, fluidity, and seamless interconnectivity across Xiaomi’s ecosystem. On the Watch S4, HyperOS is a resounding success. The user interface is clean, modern, and incredibly responsive. The 60Hz display, combined with the optimized software, results in a user experience that is completely free of lag or stutter. Swiping between screens, opening apps, and scrolling through notifications feels instantaneous and smooth. The primary advantage of a proprietary OS like HyperOS over more general-purpose operating systems is its deep level of optimization. Because Xiaomi controls both the hardware and the software, they can tailor the OS to extract the absolute maximum performance and efficiency from the device’s components. This is most evident in the watch’s remarkable battery life. HyperOS is incredibly lightweight and manages background processes and sensor activity with extreme efficiency, ensuring that no power is wasted. The trade-off for this efficiency is a closed app ecosystem. Unlike watches running Google’s Wear OS, you cannot download third-party apps from a dedicated app store. However, Xiaomi has done an excellent job of building in all the essential functionality that the vast majority of users will ever need. This includes comprehensive health and fitness tracking, notifications, Bluetooth calls, weather, alarms, music controls, and Alexa integration. For users who prioritize a smooth, reliable, and long-lasting experience over the ability to install niche third-party apps, the HyperOS approach is a clear winner. The watch also features NFC, enabling functionalities that depend on it, although the availability of services like contactless payments can be region-dependent. The inclusion of Alexa as the built-in voice assistant is another smart choice, providing a powerful and familiar interface for voice commands, smart home control, and quick information retrieval, all seamlessly integrated into the HyperOS experience.

The Ultimate Health and Fitness Companion

The Xiaomi Watch S4 is not just a smart timepiece; it is a serious and incredibly comprehensive health and fitness monitoring tool, equipped with an extensive suite of sensors and tracking capabilities that rival dedicated sports watches.

Unparalleled Activity Tracking: 150+ Sports Modes and Advanced Sensors

The watch comes pre-loaded with an astonishing library of over 150 sports modes, ensuring that virtually any activity you can think of can be tracked. This goes far beyond the basics, covering everything from running, cycling, and swimming to niche activities like dancing, martial arts, winter sports like skiing and snowboarding, and even board games. The watch uses advanced dual sensors and sophisticated motion detection algorithms to provide more accurate tracking, especially for sports with complex movements. For core activities, the data provided is rich and detailed. A running session, for example, will provide metrics on pace, distance, cadence, stride length, and heart rate zones. The inclusion of professional running courses offers guided workouts to help you achieve specific goals, like improving your endurance or fat-burning efficiency. Underpinning this vast tracking capability is a comprehensive suite of high-precision sensors:

• Heart Rate Sensor (with Blood Oxygen): The advanced optical sensor provides continuous 24/7 heart rate monitoring, allowing you to track your resting heart rate, workout intensity, and recovery. The integrated blood oxygen (SpO2) sensor adds another layer of health insight, useful for monitoring acclimatization to altitude or general respiratory well-being.
• Accelerometer and Gyroscope: These motion sensors work in tandem to accurately track steps, distance, calories burned, and sleep stages. They are also crucial for the advanced motion detection in specific sports modes and for enabling the gesture control features.
• Electronic Compass and Barometer: Essential for outdoor adventurers, the compass provides directional orientation, while the barometer measures atmospheric pressure, allowing the watch to accurately track altitude changes during hikes or trail runs and provide storm alerts based on sudden pressure drops.
• Ambient Light Sensor and Hall Sensor: The ambient light sensor automatically adjusts the screen’s brightness for optimal visibility and power saving, while the Hall sensor is part of the intelligent mechanism that detects the interchangeable bezels.

True Independence: Five-System Satellite Positioning (GNSS)

A standout feature for any serious athlete is the watch’s built-in, independent five-system GNSS. This means the watch has its own satellite positioning chip and does not need to be connected to a smartphone to track your location during outdoor workouts. The chip can communicate with five major satellite constellations (GPS, Galileo, Glonass, BeiDou, and QZSS), which is a significant advantage. By accessing multiple systems simultaneously, the watch can achieve a faster and much more reliable position lock, even in challenging environments like dense cities with tall buildings or deep canyons where the line of sight to any single satellite system might be obstructed. This results in highly accurate tracking of your route, distance, and pace, providing you with the reliable data you need to train effectively. The freedom of being able to go for a run or a bike ride with just your watch, and still get a complete and accurate record of your workout, is a truly liberating experience.

The Marathon Runner: A Deep Dive into the 15-Day Battery Life

Battery life remains one of the most critical and often frustrating aspects of the smartwatch experience. The constant need for daily charging can turn a convenient device into a burdensome chore. The Xiaomi Watch S4 addresses this pain point head-on with an impressive claim of up to 15 days of battery life on a single charge. This exceptional endurance is a result of the perfect synergy between a large battery, the power-efficient OLED display, and the highly optimized HyperOS. A more realistic breakdown for different user profiles would be:

• Typical Use: For a user with default settings, receiving notifications, tracking a few workouts per week (without extensive GPS use), and using the AOD sparingly, achieving the advertised 12-15 days is highly plausible.
• Moderate to Heavy Use: For a user who enables the Always-On Display, has a higher screen brightness, tracks 3-4 workouts per week with a mix of GPS and non-GPS activities, and uses Bluetooth calling regularly, a more realistic expectation would be a still-excellent 7-10 days.
• Intensive Use: For the power user who is constantly tracking long GPS activities, has all health monitoring on the highest frequency, and a high volume of notifications, the battery will still comfortably last for 4-6 days.

Even under the most demanding scenarios, the battery life of the Xiaomi Watch S4 Smartwatch is class-leading. It eliminates battery anxiety and fundamentally changes how you interact with the device, transforming it from a high-maintenance gadget into a reliable, ever-present companion.

Pros: The Defining Strengths of the Xiaomi Watch S4

• Stunning OLED Display and Fluid 60Hz Refresh Rate: The 1.43-inch OLED screen is a visual masterpiece, offering vibrant colors, perfect blacks, and exceptional sharpness. The 60Hz refresh rate ensures a buttery-smooth and responsive user experience.

• Innovative and Elegant Interchangeable Bezel System: This unique feature offers an unparalleled level of physical and digital customization, blending the best of traditional watch design with smart technology in a deeply satisfying way.

• Exceptional, Class-Leading Battery Life: With up to 15 days of typical use, the watch eliminates the daily charging routine, providing a level of freedom and reliability that few competitors can match.

• Comprehensive and Accurate Health and Fitness Tracking: With over 150 sports modes, a full suite of advanced biometric sensors, and a highly accurate five-system GNSS, it is a serious and capable tool for athletes and health-conscious individuals.

• Intuitive and Convenient Gesture Controls: The ability to control the watch with simple wrist movements is a genuinely useful innovation that enhances the accessibility and convenience of the device in daily use.

• Fluid and Efficient HyperOS Performance: The proprietary operating system is incredibly smooth, responsive, and highly optimized for power efficiency, contributing significantly to the watch’s excellent performance and battery life.

Cons: Understanding the Necessary Trade-offs

• Closed App Ecosystem: The primary trade-off for the efficiency and fluidity of HyperOS is the lack of a third-party app store. Users cannot install apps like Spotify, Google Maps, or other niche applications found on platforms like Wear OS or watchOS.

• Limited NFC Functionality in Some Regions: While the watch is equipped with NFC hardware, the availability of contactless payment services is often dependent on regional bank partnerships and may not be universally supported in all global markets.

• Basic Notification Interaction: While you can read notifications in full, the ability to respond is typically limited to pre-set quick replies, with no option for voice-to-text or a full keyboard.

• Gesture Control May Require a Learning Curve: While innovative, the gesture control system may require some practice for users to master the specific movements and avoid accidental triggers, potentially leading to an initial learning curve.

Frequently Asked Questions (FAQs)

Q1: How durable is the interchangeable bezel mechanism? Will it become loose over time?

The mechanism is inspired by traditional watchmaking and is engineered for durability. It uses a precise twist-and-lock system that provides a secure, tactile click when engaged. While any mechanical part is subject to wear, the system is designed for frequent changes and should remain secure and reliable for the life of the device with normal use. It provides a much more robust connection than simple magnetic or snap-on covers.

Q2: Can I install third-party watch faces on the Xiaomi Watch S4?

You are primarily limited to the extensive library of watch faces provided by Xiaomi through their official companion app. While there are hundreds of options available, covering a vast range of styles, you cannot typically install watch faces from third-party sources or app stores like Facer or WatchMaker, as you might on a Wear OS device.

Q3: Is the watch compatible with third-party fitness apps like Strava or Google Fit?

The watch syncs its data to Xiaomi’s own fitness app (e.g., Mi Fitness). From there, the Xiaomi app can usually be configured to share its data with major third-party platforms like Strava, Google Fit, or Apple Health. So while the watch doesn’t sync directly to Strava, your workout data can still get there through the intermediary step of the Xiaomi app.

Q4: How does the call quality of the Bluetooth calling feature sound in a noisy environment?

The call quality is surprisingly good for a smartwatch, thanks to the dual-microphone array with noise cancellation. In a quiet or moderately noisy environment (like a car or a busy office), the person on the other end should be able to hear you clearly. However, in very loud environments (like on a windy street or in a crowded restaurant), the microphones will struggle, and the small speaker may be difficult to hear. It’s excellent for convenience but won’t replace your phone for important calls in loud places.

Q5: What are the main differences between the Xiaomi Watch S4 and a similarly priced Wear OS watch?

The primary difference is the core philosophy. The **Xiaomi Watch S4** prioritizes **battery life, fluidity, and a seamlessly integrated hardware/software experience**. You get a much longer-lasting and often smoother device. A **Wear OS watch** prioritizes **flexibility and a third-party app ecosystem**. You get access to the Google Play Store and can install apps like Google Maps, Spotify for offline playback, and a vast array of watch faces. The trade-off is significantly shorter battery life (typically 1-2 days) and occasionally less fluid performance depending on the watch’s hardware.

Conclusion: A Masterpiece of Design, Endurance, and Intelligent Innovation

The Xiaomi Watch S4 Smartwatch is not merely an iteration; it is a bold and brilliantly executed vision of what a modern, premium smartwatch can be. It masterfully navigates the complex territory between a functional piece of technology and a desirable, personal accessory. The stunning 1.43-inch OLED display sets a new visual standard, while the revolutionary interchangeable bezel system offers a level of personalization and tactile satisfaction that is truly in a class of its own. Xiaomi has paired this exquisite design with a foundation of uncompromising performance. The marathon 15-day battery life fundamentally changes the user experience, banishing the daily charging ritual and establishing the watch as a truly reliable companion. The fluidity of HyperOS, the innovation of gesture control, and the comprehensive suite of advanced health and fitness sensors, including a highly accurate five-system GNSS, create a package that is both powerful and a genuine pleasure to use. While the trade-off of a closed app ecosystem is a valid consideration, for the vast majority of users, the sheer excellence of the built-in features will more than suffice. The Xiaomi Watch S4 is a triumph of engineering and design, a device that successfully delivers a flagship-tier experience at a price point that remains highly competitive. It is the perfect choice for the discerning user who values aesthetic elegance, a fluid and reliable user experience, class-leading battery endurance, and deep fitness tracking capabilities. It is, without question, a new benchmark in the premium smartwatch category and earns our highest, most enthusiastic recommendation.