Choosing between the Xiaomi Mi 8 and Xiaomi Mi 9 today is a classic dilemma for a buyer looking for a balance between cost and performance in the aftermarket. These two smartphones represent iconic models for the Chinese manufacturer, marking a shift to new standards of performance and design. If you are faced with choosing which of these devices will become your main device, you need to take a closer look at their technical features.
The difference is obvious, but it's not just aesthetics, the flagship lineup of the ninth series has seen significant improvements in terms of body materials and ergonomics, while the eight has remained true to proven but slightly outdated forms, and understanding these differences will help you not overpay for features that you will not use, or, conversely, not save where it is critical.
In this article, we will conduct an in-depth analysis so that you can make a balanced decision, and we will touch on the issues of speed, quality of photography and autonomy, since these are the parameters that most often become decisive when buying.
Design and Ergonomics: The Evolution of Forms
The first thing that catches your eye when you compare it is the dimensions and materials. Xiaomi Mi 8 is made of glass Gorilla Glass 5 on both sides and has an aluminum frame. It's a classic sandwich, but it turned out to be quite slippery and wide because of the "bangs" in the screen. The dimensions of the device 154.9 x 74.8 x 7.6 mm make it significantly larger than the competitors of the time.
Xiaomi Mi 9 became smaller and lighter. Engineers reduced the screen diagonal, but due to thinner bezels and the rejection of protruding bangs in favor of a neat cut-out-drop (or "eye") in the matrix, the area of usable space increased. Weight decreased to 173 grams versus 175 grams in its predecessor, which in practice feels like a greater difference due to the altered geometry of the rear cover.
- 📏 Dimensions: Mi 9 is more compact and convenient for controlling one hand due to rounded edges.
- 🎨 Design: The ninth model received a holographic iridescent backrest, which looks spectacular, but quickly collects prints.
- 🔌 Connectors: Both smartphones have retained the port USB Type-C, but the location of speakers and microphones has been revised for better acoustics.
⚠️ Note: The holographic-effect rear panel of the Xiaomi Mi 9 (Piano Black version) is extremely susceptible to micro scratches. Using a case with raised sides for the camera is critical here, since the camera protective glass is minimally protruding.
Ergonomics is not just about the size, it's about the arrangement of the controls. In the Mi 9, the buttons are a little more tactile, and the fingerprint scanner, while still optical underscreen, has been modified to make it more programmatically efficient. However, if you have large palms, the Mi 8 may seem even more comfortable because of its width.
Screen: technology of displaying information
Both smartphones received high-quality AMOLED-matrix from Samsung, but there are nuances. Xiaomi Mi 8 is equipped with a screen diagonal of 6.21 inches with a resolution of Full HD+. Brightness of 600 nits is enough for comfortable use during the day, but there is no stock. Color reproduction is configured in warm colors, which is typical for MIUI of that period.
Xiaomi Mi 9 offers a 6.39-inch panel with HDR10 support. This is a key difference for media fans. Support for extended dynamic range allows you to see more detail in shadows and lights when watching videos on Netflix or YouTube. Maximum brightness has been increased to 600 nits (in manual mode) and to 1000+ nits in automatic, making the picture readable even under direct sun.
It's worth noting that there's a protective glass. Both models use Gorilla Glass, but the nine uses a newer version that better resists falling on rough surfaces. However, as practice shows, the oleophobic coating in the Mi 9 wears off faster, and the finger begins to slide worse after six months of active play.
Performance: Snapdragon 845 vs 855
The heart of the Xiaomi Mi 8 is the Snapdragon 845 processor. At the time of release, it was the absolute top, and even today it is able to pull most modern applications and games at medium and high settings. 6 or 8 GB of RAM ensures smooth interface operation, although in heavy multitasking scenarios, applications can be unloaded from memory more often.
The Xiaomi Mi 9 received the Snapdragon 855 chip, which was a real leap in performance. The Adreno 640 graphics accelerator shows a 45% increase over its predecessor. This means not just power reserve, but a fundamentally different level of comfort in demanding tasks such as video rendering or running games like PUBG Mobile and Call of Duty.
| Characteristics | Xiaomi Mi 8 | Xiaomi Mi 9 |
|---|---|---|
| Processor | Snapdragon 845 (10 nm) | Snapdragon 855 (7 nm) |
| AnTuTu (roughly) | ~300,000 points | ~450,000 points |
| RAM | LPDDR4X | LPDDR4X (faster) |
| Storage | UFS 2.1 | UFS 2.1 (optimized) |
The difference in process technology (10 nm vs 7 nm) also affected energy efficiency. Snapdragon 855 less warms up under load, which allows the phone to keep the peak frequency longer without trottling. If you plan to use a smartphone for mobile games, the choice in favor of the Mi 9 looks like no alternative.
💡
For games on Xiaomi Mi 9, be sure to turn on the Game Turbo mode in the security settings. This will redistribute the CPU resources in favor of the running game, disabling background processes.
Cameras: three-time zoom and artificial intelligence
The photography capabilities are where the Xiaomi Mi 9 really went far ahead.The main module was the Sony IMX586 sensor with a resolution of 48 MP. Unlike the 12-megapixel module in the Mi 8, the new camera allows you to take pictures with high detail in daylight and use the second-generation night shooting mode, which works wonders in the dark.
The main advantage of the Mi 9 is the presence of a telephoto lens with 2x optical zoom. In the Mi 8, the second module was also a TV, but without optical stabilization and with worse aperture. In the nine, a third, ultra-wide-angle module at 16 MP, which allows you to capture panoramic landscapes, which makes the camera set a versatile tool for any scenario.
- 🌙 Night Mode 2.0 in Mi 9 can withstand exposure for up to a few seconds, creating vivid shots without noise.
- 🔍 Zoom: Optical zoom in Mi 9 allows you to zoom in without loss of quality, unlike the digital crop in Mi 8.
- 🤳 Selfie: Front camera in Mi 9 (20 MP) received support AI-sensitization and improved work with HDR, make the skin more natural.
⚠️ Note: The 48MP shooting mode in the Xiaomi Mi 9 is activated manually in the "More" menu. In standard mode, the camera uses pixel-binning technology, combining 4 pixels into 1 to get a 12MP shot with better light sensitivity.
Video shooting has also undergone changes.The Mi 9 learned to write 4K video at 60 frames per second, while its predecessor is limited to 30 frames at maximum resolution. Image stabilization in the ninth model has become smoother, although the optical stub only works on the main and body modules.
Autonomy and charging: the race watts
Battery capacity in Xiaomi Mi 8 is 3000 mAh, which even for 2018 was not much. Given not the most energy-efficient 10nm processor, the smartphone barely survived until the evening with active use. Xiaomi Mi 9 received a battery of 3300 mAh. It would seem, the increase in small, but thinner process technology allowed to increase the screen time by about 15-20%.
The real breakthrough, however, came in charging speeds. The Mi 8 supports fast charging of the Quick Charge 3.0 with 18 watts. It takes about 2 hours to fully charge. The Xiaomi Mi 9 was one of the first smartphones to support 27 watt wired and, more importantly, 20-watt wireless charging. This allows you to recharge the battery from 0 to 100% in less than an hour.
☑️ Checking the status of the battery used smartphone
It is important to consider that the 27W power supply complete with the Mi 9 was only in the global version, the Chinese version could be different, and to implement wireless charging, you had to buy a special mat separately, since it was not in the box.
Software and relevance
Both phones came out with Android 8 and 9 respectively. For now, official support for Android updates has been discontinued for them, and they have settled on the version of Android 10 with the MIUI 12 shell. This is a critical point: devices no longer receive security updates, which may be important for those who store sensitive data.
However, the development community is actively supporting these models. For Xiaomi Mi 8 and Mi 9, there are many custom firmware (LineageOS, Pixel Experience) available, which allows you to upgrade to more recent versions of Android. Thanks to the popularity of these models, finding stable build and installation instructions is not difficult.
Should I install a custom firmware?
In terms of out-of-the-box optimization, the Mi 9 is more stable; the more powerful processor is better at handling heavy MIUI interfaces, is less prone to micro-freezes when scrolling through social media feeds; and the Mi 8 sometimes has twitching animations, especially when there is a lack of free RAM.
The final verdict: what to choose in 2026?
To sum up the comparison between the Xiaomi Mi 8 and Mi 9, these are two different classes of devices, despite belonging to the same lineup: the eight is a reliable “middle” of its time, which today will suit as the first smartphone for a child, a device for navigating in a car or a phone for elderly parents who do not need complex functions.
The Xiaomi Mi 9 is still a full-fledged flagship that can meet the needs of a demanding user. The best camera, HDR support, high performance and fast charging make it relevant today, especially given the decline in the price in the secondary market. If the budget allows, the overpayment for the Mi 9 is fully justified.
💡
Xiaomi Mi 9 beats Mi 8 on all fronts: camera, screen, processor and charging. the difference in price in the used market is minimal, so the Mi 9 is the uncontested leader in this pair.