Xiaomi Mi MIX Review

After a surprising launch almost two months ago along with the Mi Note 2, Xiaomi Mi MIX has easily become not only the most discussed smartphone of the year, but also the most innovative one in terms of design and build. Selecting a high-profile designer like Philippe Starck for its latest flagship smartphone and revealing a well-thought-out project, Xiaomi clearly demonstrates that it has been ready for quite some time to make the big leap from a regular OEM to a trendsetter in the smartphone market. The company has already announced that it will also take part for the first time in the Consumer Electronics Show (CES) in Las Vegas next month. This is yet another step to expanding its international reach. Whether the new "concept" phone will meet expectations and will bring not only interest, but also recognition in the long term - only time can tell, but it definitely puts Xiaomi on the right track of becoming a serious competitor in the global smartphone market. So without further ado, let's start our in-depth review of the Mi MIX with its official specifications.

Specifications

Xiaomi Mi MIX boasts a custom-made 6.4-inch IPS display from Sharp that graces a full ceramic body. It has an aspect ratio of 17:9 and a resolution of 1080 x 2040 pixels. The static contrast ratio is 1300:1 and the peak brightness reaches 500 cd/m². The display panel covers 94% of the NTSC color space. More interestingly, this is the first smartphone display panel that has rounded corners, which facilitate the creation of an edge-to-edge screen. The all-ceramic body houses a Qualcomm Snapdragon 821 MSM8996 Pro chipset created after the 14nm process and including a 64-bit CPU that contains two Kryo cores clocked at 2.35GHz and another pair of Kryo cores ticking at 2GHz. The graphics are handled by a Qualcomm Adreno 530 GPU clocked at 653MHz. The classic variant of the model sports 4GB of double-channel, LPDDR4 RAM clocked at 1866MHz and 128GB of UFS 2.0 internal memory. The Exclusive Edition has 18K golden rims around the camera and fingerprint sensor along with 6GB of RAM and 256GB of storage. The rear-mounted, ultrasonic fingerprint sensor is ceramic as well and is made by Fingerprint Cards - FPC1235. The primary camera is equipped with a 16-megapixel OmniVision OV16880 PureCel sensor and an f/2.0 lens. It is aided by a dual-tone LED flash and phase-detection autofocus. The shooter can make 4K and slow-motion videos. The front-facing snapper packs a 5-megapixel OmniVision OV5675 sensor and an f/2.2 lens. The device is also meant to provide high-resolution audio (192 kHz at 24 bit). It relies on a 4400 mAh battery to keep the lights on. The accumulator supports Quick Charge 3.0 and arrives with a 5;9;12V/2.5;2;1.5A fast charger. For complete details, here is the full list of Xiaomi Mi MIX specifications.

What's in the box

The packaging of Mi MIX is nothing you've seen before. You receive a bulky, black box with a black cover that has the 128GB sign on one side (designating the version you get) and a sticker with basic specifications at the bottom. The 256GB version has a gold sign on top of the lid, which reads "MIX designed by MI". When you take off the cover, you get access to the box itself. Its lid has the MI logo in black debossed on it and is attached to one side by a magnet. When you open it, you unveil the top level compartment with the smartphone lying in it. Then the box just unfolds in front of your eyes, revealing the other two compartments below. The design of the box and accessories follows the minimalist design of the smartphone. The second compartment contains a European ecco leather case for protecting the device's back and sides if dropped. Each case is handmade - individually cut, ironed, and bound by highly skilled craftsmen. The third one is where the user manual, warranty card and SIM tray pin are placed together with a USB to USB Type-C 3.0 cable and a charger - all this packaged in two separate small boxes. The power adapter is typical for Xiaomi - it has two flat pins and no grounding area. This is the so called US NEMA-1 wall plug standard and it is used in the US, Canada and some Latin American countries. If you reside outside these places, you will most probably need an adapter.

Design, build and controls

It is not possible to discuss the design of an innovative gadget without explaining the design philosophy, intertwined in every small detail of the device. Created by French designer Philippe Starck, Mi MIX personifies his philosophy of "Less material, more humanity". Put in simpler words, this is minimalism put in service to the people. It is not the device that's important, but its ability to help you see the world the way that it is. That has lead to creating a smartphone with an edge-to-edge display, which is the main focus of Starck's design. To support this, in a video made by Xiaomi, the designer says: "We don't want pollution, we just want the image," and then adds, "It's the content that's important", "I want to see the person I love, nothing else." A second major point of focus for the design is the material used for the smartphone. Starck says that "Ceramics is magic Poetry. It's incredibly strong, and it's warm. It's the same structure as jade." Ceramics has been described by him as being "the oldest and most contemporary of materials", which, again, makes a parallel with the human aspect of design. So let's get a bit deeper into those design details. For starters, this is the first smartphone with, let's say, an all-ceramic body. The back plate, frame, buttons and even some internals are ceramic. The end result is achieved after the high-grade micro-crystalline zirconia ceramic material has undergone a 7-day, 1500 ℃ high-temperature calcination process, which turns it into a deep black and a very hard ceramic, with a hardness close to that of sapphire. More specifically, this material starts to be scratched at 8.5H from the MoHs scale for glass hardness, which is truly impressive! 10H is the highest point and corresponds to the hardness of diamonds. It appears that not only the back, but the frame, buttons and rear-mounted fingerprint sensor are ceramic with such a level of hardness. The lens of the primary shooter is protected by a special glass, which cannot get scratched easily, too. All this means that everyday objects cannot harm the Mi MIX in any way. However, the ceramic material is quite fragile and does not need a lot in order to crack. That's why working with this material during production is risky - it is extremely difficult to produce large quantities without losses (units that crack during production). This is one of the reasons why Mi MIX is produced in limited numbers. The company does have experience with this material from the production of the Mi 5 Ceramic Edition, so this is a plus. In addition, ceramic fragility brings a risk for the smartphone to break down, if accidentally dropped even not from very high. What's worse is that the edge-to-edge display can get easily cracked, too, due to the lack of protection/isolation between the screen and the ceramic frame. We think that using the leather case for the device is a must, if you want to be on the safe side. Ceramic is also very glossy, glossier than glass covers and just as them - prone to being smudged with fingerprints. Another interesting design and build feature of this device is that the frame and back use the mortise and tenon joint style of fitting, which is thousands-of-years old and has been used not only in Asia, but also in all parts of the world mainly by woodworkers. Placing a 6.4-inch display that spans from edge to edge (left, top and right) in a frame that is more suited for a 5.5-inch smartphone opens a number of issues, which Xiaomi has cleverly solved. It has, actually, made the radical design decision to get rid of the whole top part and internals that are found in all smartphones today. This includes the earpiece, front camera and proximity sensor. Let's start with the earpiece. Mi MIX is equipped with a cantilever piezoelectric ceramics acoustic technology, which replaces the traditional earpiece/speaker in a smartphone. How does it work? You receive a call and you pick up. The piezoelectric ceramic component converts the electric signal into mechanical energy. This generates vibrations resonating in the frame of the phone, which are then converted into sound waves. The cantilever is attached to this component and serves as a booster for the vibrations. Hence, you're able to hear the caller. One thing should be noted though - the sound can be heard from any place on the frame and from the back of the device (the top area). This means that the sound does not have the traditional direction it receives from a typical speaker. We have tested whether someone may eavesdrop your conversations in a quiet and normally noisy environment and this is further discussed in the networks and call quality section of this review. A second innovative solution in this device is the use of a built-in ultrasonic proximity sensor. Traditional proximity sensors used in smartphones are optical infrared hardware ones placed above the display. If Xiaomi has decided to keep it, it wouldn't have been able to extend the display to the top edge, so finding a solution has become a must. The company has been cooperating with Elliptic Labs for about an year to create a suitable solution for this issue. Mi MIX employs Elliptic Labs' patented ultrasound proximity software called Inner Beauty. On one hand, this technology creates enough space to extend the display and to place behind it the cantilever piezoelectric ceramics speaker described above. On the other, the solution reduces the cost as the hardware sensor is removed. Moreover, it provides better sensitivity and solves issues that are typical for hardware sensors such as their unreliability when operating in certain weather conditions, for example. Just like in ceramics, Xiaomi has a previous experience with ultrasonic technology. If you remember, the company uses an ultrasonic fingerprint sensor in the Mi 5s. It looks like ultrasonic technology will find even more practical applications in mobile devices. It creates high-frequency waves, which are called ultrasonic because they are beyond the limit of human hearing, which normally is in the 20Hz-20KHz range. These are mechanical vibrations that can be used to measure thickness, detect flaws in materials, etc. In this particular case, these waves are able to flawlessly detect your face or any other obstacle in front of the device and make the smartphone react accordingly. The third design issue that has found a corresponding solution is the placement of the front camera. Xiaomi has re-designed a camera module to make it 50% smaller than the traditional one and has placed it at the bottom right corner of the smartphone below the display. If you don't find it convenient to make selfies this way, simply turn the phone upside down. The ambient light sensor has found a non-traditional place, too. It is located in the center of the chin, right below the screen. With the chin being already occupied, Xiaomi has opted for on-screen navigation, which is complemented by the Quick Ball - a floating dot that can serve as a navigation tool as well. The on-screen navigation can be managed from the corresponding menu in the Additional Settings. We must say that this is the first on-screen navigation, which we like. It is cleverly designed and in no way interferes with your interaction with the device. Actually, we think that Xiaomi have opted for the non-standard vertical resolution of 2040 pixels, simply to preserve the original 1920 pixels for the content and the rest of 120 pixels to be used for the software navigation bar. The rest of the controls are quite traditional. The dual-SIM tray is positioned in the upper area of the left frame. The volume and power buttons, which are ceramic, are positioned on the right frame. The top frame houses a 3.5 mm jack, while the bottom one features symmetrical speaker grilles on both sides of a USB Type-C 3.0 port. The left one is for the microphone, which faces only one of the holes, and the right one is for the speaker itself. On the back of the device, centrally along the vertical you will see the primary camera, covered by protective glass with the dual-tone LED flash to its right, and the ceramic, ultrasonic fingerprint sensor below it. Then the "MIX designed by MI" sign follows. The smartphone is only 7.9 mm thin, which is quite impressive having in mind its solid build and large battery (4400 mAh). It is on the heavier side though (209 grams), but one hand this is expected due to the large battery and big display, on the other, this means that nothing has been spared in terms of components and material quality. Still, it is one of the lightest smartphones in its size class. In terms of width and height, which measure 81.9 mm and 158.8 mm, respectively, this is the most compact device among those with a 6-inch display or larger.

Display

After the Sharp Aquos Crystal, Mi MIX is the second officially released smartphone that has a three-sided bezel-less display. Bezel-less in this case means that the display is edge-to-edge, or frame-to-frame. The frames are very thin, indeed. However the more important fact is that Xiaomi has employed a number of clever innovations and design solutions that actually elevate the idea of a device with such a display to a whole new level. Probably it won't come as a surprise to you that precisely Sharp is the manufacturer of the display panel used in the Mi MIX. Aida64 reveals that this is a Sharp FTE716 DSI (Display Serial Interface) panel. Xiaomi has customized it by creating an unusual aspect ratio (17:9) and unusual resolution (1080 x 2040) along with making the panel corners rounded! Yep, this smartphone is the first in the market with rounded corners, which actually make getting rid of the bezels much easier and are in unison with the rounded frame corners. The diagonal size is 6.4 inches and the display takes up 91.3% of the total front surface of the device. To those of you who have concerns about accidental touch input, we must say that handling the Mi MIX is in no way different than that of any other smartphone. The screen rejects any touch that is not made by a fingertip. The only area that does not have accidental touch rejection area is the upper edge. Have this in mind, if you rotate the phone upside down to take selfies or if you watch videos/play games in a landscape position. As long as it concerns glass protection, such is not specified, but the display starts to scratch at 6H from MoHs scale of glass hardness with more serious marks at 7H, which means it is as protected as any other flagship in the market today - iPhone 7 or Samsung Galaxy Edge 7, for example. The display has a very good peak brightness, which corresponds to the officially specified one: 500 cd/sq.m. This might not provide best viewing experience under direct sunlight, but is bright enough. More importantly, this is one of the rare display panels that has a very even brightness distribution. This means that the white luminance values of different areas of the display (not only the center) at one and the same brightness level do not differ a lot. The black luminance values are fine, and though the contrast ratio is not as high as the one of the Mi 5s, for example, Mi MIX shows a very good contrast ratio of 1600:1 - higher than the one specified. Another tell-tale sign for a quality display is the relatively even temperature of the white point at the different brightness levels. In this case, it varies with only a little from 7030 K to 7367 K, which is an excellent measure. This is also a normal value for a screen of a mobile device.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	507.669 cd/m2	0.335 cd/m2	1515	7367 K
75 %	281.236 cd/m2	0.171 cd/m2	1645	7211 K
50 %	147.898 cd/m2	0.092 cd/m2	1608	7127 K
25 %	60.419 cd/m2	0.037 cd/m2	1633	7045 K
0 %	6.275 cd/m2	0.000 cd/m2	-	7030 K

The display panel has a striped sub-pixel geometry. It covers 94% of the NTSC color space with the deviations in the green area being more significant than those of the red and blue one. In case you need to change the color temperature (reading mode), contrast and/or saturation you can do so from the Display menu in the Settings. The viewing angles are excellent - the colors are preserved and there's only a minimal loss in brightness, if you look at the display from an angle. Our measurements show that the display panel used for the Mi MIX is of high quality. The overall impression of the display is that a 1080p resolution on a 6.4-inch diagonal size is more than enough. The unit is very responsive and super convenient for reading and browsing due to its size.

OS, UI and software - vendor ROM

Our review unit arrived with a vendor ROM (v 8.0.8.0 M0AHCNDI), which is stripped off of most of Xiaomi's services and has added Google ones instead. Usually vendor ROMs are not bound to receive updates in any way. The only Xiaomi apps that have been preserved in this case are the Music, Security, Themes, Video, Sound Recorder, Explorer and QR Scanner apps. All of these have been limited in terms of access to content and functionality compared to their originals. The Calculator lacks its additional services such as metric conversions. The QR Scanner lacks some of its additional functionalities, too. There are no shortcuts to the Music and Security app on the home or any other screen - you have to access them via the Explorer or from the list of apps in the app management settings. All other apps and services installed on the device are fully functional. The Notes up is entirely different and not as pretty as the original Mi one. The Phone app lacks the Yellow Pages service (tab). A different keyboard is used, which is not as quick and intuitive as the Sogou one used in the original MIUI 8. The default browser is not the same either and offers limited options. The Notifications and Quick Settings shades are joined in one with the option to be split, the Task Manager and Widgets menu are typical MIUI 8 ones, so are the Volume and Power Off shades. The Settings look familiar, but there are some minor differences as well, such as the presence of the Google menu in the Accounts management, for example. We had to dig a bit deeper as well and noticed that in the Developer options the "Mi Unlock Status" option is missing. So you cannot check whether your bootloader is locked or not, and in case it is locked and you have to unlock it - there is no way to do it.

OS, UI and software - original China developer ROM

We strongly believe that original UIs, being created from the manufacturers especially for the devices that the produce, reveal the devices' full potential. Having in mind the vendor's ROM limitations described above, we decided to place the original China developer ROM on the Mi MIX. We used the deep flash method with a DIY cable and managed to safely install the latest version. China Developer ROMs are almost the same as the China Stable ones, however, they are updated weekly and contain many new features that will be available in stable ROMs in the future. China ROMs have Chinese (Simplified and Traditional) and English languages, and do not include Google Play Services as they are banned in China. Instead, they provide similar tools for the Chinese market. The latest MIUI is version 8 and is based on Android 6.0 Marshmallow, but in terms of looks it is far away from it. We have discussed it in detail, including the differences with MIUI 7, when we have reviewed previous Xiaomi smartphones. So let's start with the basics of the UI. When you start the device for the first time, you can set up several things like the language and whether you want to have a Wallpaper Carousel for the lock screen activated. In this case we chose to have one. The lock screen is as clean from clutter as it can be. A single shortcut to the Camera app is coupled with the swipe-up option for unlocking and a clock widget. If you want to add a second shortcut in the left corner, or switch shortcut places, in MIUI 8 you can do so from the corresponding settings in the Lock screen & password. There is a whole new set of beautiful wallpapers in addition to the ones you're already familiar with. Unlocking leads you to the home screen, which has a row of docked apps - the same as with other MIUI 8 phones - Dialer, Messenger, Browser, and Camera. Above it there are three rows of apps and a Tools folder. The second screen contains the rest of the apps and another folder called More Apps. As usual, the Task Manager is accessed by tapping on the menu button. You can view the open apps as a row of small windows or as a row of app icons. The view can be changed from the icon on the top right corner of the Task Manager. In both views you can lock/unlock an app and access its detailed information screen. The Volume shade is no longer circular like in previous MIUI versions, but is more similar to the classic Android 6.0 one and contains all three volume types. Evidently, the developers at Xiaomi have managed to fix a small issue as this is the first time, in which we were able to make a screenshot of the Volume shade. In all previous cases it disappears at the moment a screenshot is taken. It is the same with the Quick Ball. The Power off options are the four traditional MIUI ones - airplane and silent modes, reboot and power off. The eighth version of MIUI is the first one to combine the Notifications and Quick Settings into one shade. This latest developer version reveals several improvements such as the addition of a quick search bar on top of the shade, merged with the basic weather information and a shortcut to the Settings. Next to the Settings icon there is a new one, which allows you to change the way the Quick Settings toggles appear on the single shade - they may either appear in one swipable row or be listed in full on one screen. Then the brightness level bar follows with the list of Notifications. If you like the old style, which lists the two services in two separate shades, you can choose this option from the Settings. In this case, the Notifications shade appears first and the Quick Settings are accessed by swiping from this shade to the left. A tap and hold on the menu button opens the Widgets menu. You can also activate it by zooming in with two fingers on the home screen. Typically, it is an extensive one and allows you to move apps and folders from one screen to another, to place a toggle, shortcut to selected settings and various widgets on screen(s) of your choice. Of course, you can change the wallpaper and screen transition effect. Under this menu you can also choose the style of the clock widget by clicking the icon to right of this widget. The Settings menu in this latest MIUI 8 version has colored icons in front the menus. It starts with a search bar, which lets you find quickly menus and functions that contain a certain letter/word. The search bar is followed by the Network group of settings, which traditionally lets you manage the SIM cards and mobile networks, wireless connections, and other related options. The second group is called Personal and is used for personalizing the display, sounds, wallpapers and themes on your device. The Display menu contains a brightness level bar, reading mode (it can be set to switch one for selected apps, too), color & contrast settings, text size, auto rotate and double tap to wake toggles. The Wallpaper and Themes menu offers access not only to offline content, but also to online one. Once you access the online content, you're actually using the Theme app with all of its extensive features, which will be discussed in more detail in the following sections of this review. The Sound & vibration settings provide a Silent Mode toggle, level bars for the three volume types, ringtones and notifications sounds, vibrations and system sounds. This sub-group also contains the advanced settings for headphones and audio, which can be accessed from the Music app and from the Additional settings as well. The third main Settings group is named System & Device. The first menu under it is the Lock screen & password one. It contains the screen lock and fingerprint options, a set of shortcuts for two apps on the lock screen, smart cover mode behaviour management, etc. The second sub-group under System & Device is the Notifications and status bar. It is precisely this set of options that allows you to switch between a merged and separated Notifications/Quick Settings view, to change the toggles positions, manage the app notifications, and customize the way the status bar looks like with toggles for the connection speed, battery indicator, notification icons, carrier name, etc. The third sub-group and probably MIUI 8's most noteworthy feature is the Second Space. It creates a virtual machine, which has the full functionality of a separate smartphone. You have apps for managing it, switching between the two spaces and importing/exporting data to from/the second space. The Do Not Disturb menu is the fourth sub-group and provides toggles for switching DND on/off. You can also make DND schedule, set exceptions and sounds for special events. The Battery and Storage menus will be discussed later in this review. The latest MIUI 8 does not contain Lite Mode, like the very first editions of this UI version. The last sub-group is the Additional Settings one and it includes all settings that do not "fit" the other groups. Starting with the Date & time, it continues with Language & input, Locale, Child mode and Privacy. The Child mode can be set for specific apps and for additional security you can set it to be activated/deactivated only after fingerprint identification. Quick Ball has been present in MIUI 8 since its first edition. In Xiaomi Mi MIX this functions receives a whole new meaning as the only navigation you get in this model is the on-screen one and the Quick Ball can be accessed from the navigation bar, too. This is a floating dot that can be used as an alternative to the navigation bar. It can be customized in such a way as to serve you in the most convenient way. You can also manage the appearance and function of the on-screen buttons. A first-time feature in MIUI 8 is the Screenshot menu, which lets you choose whether making a screenshot should be accompanied by a sound and to toggle making a screenshot by sliding three fingers on the screen. The Additional Settings also contain Notification light ones along with the Headphones and audio effects menu, Accessibility and Mi Mover. One-handed mode is present here as well and for such a device it might come in handy, especially for people with smaller hands. Accounts is the fourth main group of Settings. It lets you manage your MI account (if you have one, it's not obligatory unless you want to access all Chinese content available through the MIUI apps) and other accounts you might have on your device. There's also a Sync option for synchronizing data between them. The last group of settings is the App Settings one. It lets you view and manage the settings of system apps and additionally installed ones, as well as activate the Dual apps function. The latter allows you to use two separate logins in one and the same app, WeChat for example. Thus you can keep your personal and work life separated and organized. Of course, there are app permissions and lock settings for additional security. The About Phone menu is last as usual and besides all standard data contains a shortcut to the system updater. The apps in MIUI 8 are directly installed and appear on successive screens starting with the home one. You can move them as well as store them in folders and move the folders, too. Moving an app to the recycle bin that appears means you will uninstall it. However, a confirmation dialogue prevents you to do so by mistake. The home screen contains a row of docked apps, which appears on every following screen, too. These are the Dialer, Messenger, Browser, and Camera. In the original Chinese version, the Dialer has three tabs - for the dial pad, contacts and yellow pages. This tab is absent in adapted and global ROMs. The Contacts can also be accessed from a separate app in the Tools folder. The Messenger is very simple, quick and intuitive. The default browser in MIUI 8 is very quick and pleasure to work with. It offers a choice of search engines, has a night mode and a built-in add-blocker as well as many other features to make browsing more convenient. The Weather and Notes are as beautiful as useful. Of course, having a China ROM means you'll get a whole suite of Mi apps, which create a media content eco-system. These are the Mi App Store, Mi Reader, Mi Video, Mi Games, Mi Wallet, Mi Home, Mi Live, and many others. The Tools folder contains useful apps such as the calculator, which provides many options for converting various metrics, currencies, mortgage rates, etc. The Explorer is MIUI's file manager, which besides providing various ways of previewing files on the smartphone, allows you to manage this content and optimize your storage. The Clock app is the well-known four-tab app that contains the alarm, clock, stop watch and timer tabs. Of course the Updater is present as a separate app, not only as a shortcut in the About Phone menu from the Settings. The proprietary Video app of MIUI offers some basic options for video editing such as audio enhancement, aspect ratio and brightness. The Sound recorder is also customized and the new ROM contains a Voice Assistant as well along with the already familiar Compass, Level, QR scanner, Mail, Mi Account, Downloads, Virtual SIM, Feedback, VideoCall. The More Apps folder contains the WPS Office, Qunar Travel, Weibo, Mi Life, Mi Talk, QQ Chat, MIUI Forum, and iQiyi (Chinese online video platform) apps. The Security app is present as well and as usual contains Cleaner and Virus scan, App Lock and Permissions, Data usage and Block list, along with the Battery management. The Themes app, offers lots of free content and customization options. It has a main page with several tabs - for the themes and wallpapers (lock and home screen ones), ringtones and fonts. For each there are top charts and categories, which list online themes and wallpapers, ringtones and fonts. The downloads section contains the ones you download and the ones that are already available offline by default. This app also allows you to change the appearance of the Lock style, Status bar, Icons, Messenger, Dial pad and Favorites tray. All this can be managed from one Themes home screen, from where you can also login to your Mi Account, if you have one.

Networks, calls and connectivity

Xiaomi Mi MIX has a dual nano-SIM card tray with both cards working in a dual SIM standby mode. Similar to other flagship smartphones by the company, this model supports many network bands, including 2G GSM (850, 900, 180, 1900 MHz), 2.5G CDMA (800 MHz), 3G TD-SCDMA (1880-1920, 2010-2025 MHz), 3G UMTS (850, 900, 1900, 2100 MHz), 4G FDD-LTE (850, 900, 1700/2100, 1800, 1900, 2100, 2600 MHz), and 4H TDD-LTE (1900, 2300, 2500, 2600 MHz). LTE downlink and uplink speeds are Cat. 12 ones. The cantilever piezoelectric ceramic speaker that replaced the traditional earpiece is very loud at its maximum volume and we could even feel the vibrations. The sound coming from it at normal volume levels is fine. It sounds a bit muffed compared to a standard earpiece, but is no less distinct. So you won't have any issues with making phone calls. VoLTE is supported, too, along with full NFC functionality - read, write, card emulation, P2P, Mi Pay ready. The device supports dual-band Wi-Fi 802.11 a/b/g/n/ac with MU-MiMO, 802.11n 5GHz, Wi-Fi Hotspot, Wi-Fi Direct, Wi-Fi Display, and Bluetooth 4.2. It is equipped with a USB Type-C 3.0 that supports OTG and a 3.5 mm jack. All these connectivity options and features work fine. Finally, the smartphone packs SAP (sensor-assisted positioning) GPS technology and supports not only GPS, but also Glonass and BeiDou. It managed to detect satellites from all three systems quickly and with an excellent accuracy.

Performance

Mi MIX relies on the 64-bit Snapdragon 821 MSM8996 Pro in its top variant (2.35GHz) to skyrocket it to the top of the benchmark charts. This is the current most powerful system-on-chip on the market. Built after the 14nm process, it increases performance by 10% in comparison to the Snapdragon 820. It retains the CPU architecture comprising of four custom Kryo cores, which, however, are clocked at a higher rate. To be more exact, the CPU includes two 2.35 Kryo cores and another pair of the same clocked at 2GHz. The graphics depend on an Adreno 530 GPU clocked at 653MHz, which increases performance by 5% compared to the same GPU in Snapdragon 820. Performance and battery life are further improved by the presence of the new Qualcomm Hexagon 680 DSP. Among all else, Snapdragon 821 MSM8996 Pro supports VR headsets, too. We have already managed to test it on the Mi 5s Plus and the Mi 5s. Logically, its benchmark results are on par with those of Mi 5s Plus as this model is also based on the 2.35GHz variant of the chipset. With an AnTuTu result of 162521 points, the Mi MIX proves to be the most powerful smartphone (according to this test), we've reviewed so far. It is followed closely by the Mi 5s Plus, which has almost the same result. The rest of the benchmark tests also demonstrate the model's superiority. Even in PCMark and 3DMark tests, which are one of the most serious ones, Mi MIX shows enviable results. We are reviewing the 4/128GB version of the model. There's a 6/256GB variant, called "Exclusive Edtion" because the rings of the rear camera and the fingerprint sensor are made of 18K gold. The RAM is double-channel, LPDDR4 clocked at 1866MHz and the internal memory is the UFS 2.0 type one, which is the current fastest in the market. Literally, you cannot feel the phone struggle with none of the apps and games you though at it. The RAM is more than enough and the chipset is a real beast. The internal storage is quite generous, no expansion available. Of 128GB on board, 120GB are available to the user. Reading and writing speeds from/to the memory are super fast and correspond to its type. There's a plethora of sensors on board, including Elliptic Labs' proximity sensor along with an accelerometer, compass, gyroscope, barometer, Hall sensor and of course - an ultrasonic fingerprint one made by Fingerprint Cards (FPC1235). It actually demonstrated being quite sensitive, because it managed to detect a fingerprint even through the protective foil on the back with which the device arrived. Accuracy is fine. It is a bit trickier to adjust your finger, if you use the protective case and in those cases recognition might fail more often due to poor finger positioning.

Cameras

Тhe camera app is a typical MIUI 8 one. The home screen contains a large circular shutter button, with a smaller circle to its left that leads to the list of photos, and another one to the right that switches to video mode. Above it a shortcut to the Modes is positioned with a shortcut to the filters to its right. At the upper left corner of the home screen of the app are the flash options and at the right one - the HDR settings. The 10 modes include panorama, timer, audio, manual, straighten, beautify, HHT, tilt-shift, Group Selfies, and Square. The manual mode is the most interesting one and allows you to manually adjust the focus, exposure time, white balance and ISO. The app offers separate settings for the rear camera in photo and video mode, and separate settings for the front camera in photo mode. Some of the most distinctive options of the rear camera are the QR scanner, enhance lowlight photos automatically, flash settings, saturation, contrast, sharpness, etc. The video settings of the rear camera include image capturing while shooting, focus mode, time laps interval, image stabilization. For the front camera there is a mirror function, triggered when a face is detected. Of course, for any of these you can set picture/video quality, toggle camera sounds and location info saving, etc. The camera app in MIUI 8 has a standard set of editing options once after you take a photo. In our review unit the first option is to apply a filter. The second is to adjust the frame. The rest allow you to add stickers and watermarks. You can share or delete a photo, set it as a wallpaper or a contact photo, insert it in a slideshow or add it to an album and receive more information about the file itself with the photo's properties.

Primary camera

Mi MIX features a 16-megapixel rear camera equipped with an OmniVision OV16880 PureCel sensor with a 4.26 mm focal length. The sensor's size is 1/3.06", while the pixel size is 1 μm. The lens has an f/2.0 aperture. The camera makes photos with a resolution of 4608 x 3456 pixels and is capable of shooting 4K video (3840 x 2160) at 30 fps and 720p video at 120 fps. The panoramas are with a resolution of 7232 x 1728 pixels. The shooter's work is aided by phase-detection auto-focus and dual-tone LED flash. Due to the second-generation ISP from Qualcomm, which is on board, the camera also employs a dark light enhancement technology. LeEco Le 2 (X620) uses the same camera sensor, so you can compare how both devices' cameras perform.

Secondary camera

The front facing camera's sensor is supplied by OmniVision as well. It is a 5-megapixel one, model OV5675. It has 1.12 μm pixel size and a 4.6 mm focal length. The lens is with an f/2.2 aperture. The photos are with a resolution of 2592 x 1944 pixels. The shooter can record FHD videos at 30 fps.

Audio

The Music app in MIUI 8 has many features and in the Chinese version, similar to the Themes app, it provides access to tons of online content and even allows you to stream music. The main screen of the app opens the online content home page with shortcuts to the home screen of the app, which includes a folder for offline content and a favorites one, too. Below them appear any playlist you might create and at the bottom you will see the player itself in minimized view. There are additional tabs that group your audio files according to the file name, the name of the album and artist, etc. When you tap on the minimized player, it will expand to full screen with options for opening the Headphones & audio effects settings. Besides all else (headphones button adjustment, choosing headphone type, switching the equalizer on/off, etc.) you can also switch on the HD Audio effects. The only known special audio feature of Mi MIX is that the smartphone offers high-resolution audio - 192 kHz / 24 bit. Mi MIX shows audio results that are comparable to those of Mi 5s and Mi 5s Plus. It excels in frequency response only and is average in THD + Noise. The rest of the parameters are evaluated as being Very good and so is the final result. Actually, the results are so similar that they pinpoint to the fact that one and the same hardware has been used in all three smartphone. This is just an assumption, of course. As usual, we perform our audio test by using the TASCAM US-2x2 audio interface and the RightMark Audio Analyzer software. All audio enhancement features are disabled. The results in the table below refer to the audio system of the device and do not take into account the speaker. In the case of Mi MIX, the latter provides better sound than the average smartphone speaker, but this is just a subjective opinion.

Test	Value	RMAA rating
Frequency response (from 40 Hz to 15 kHz), dB	+0.01, -0.08	Excellent
Noise level, dB (A)	-94.8	Very good
Dynamic range, dB (A)	94.8	Very good
THD, %	0.0071	Very good
THD + Noise, dB (A)	-80	Average
IMD + Noise, %	0.0089	Very good
Stereo crosstalk, dB	-81	Very good
IMD at 10 kHz, %	0.015	Very good
General performance		Very good

Battery

The Security app is an integral part of MIUI 8. One of its six main services is the Battery & performance one. It provides you with tools to analyze your battery, solve the issues (if such are found), and suggests further improvements. You can monitor which apps and hardware parts consume the most power and act accordingly. You can also manage the battery usage for individual apps. There's a Battery Saver on board, which is switched off by default and combined with scheduling options. Schedule power on & off is present, too. There are special settings for additional power saving such as options to turn off mobile data and/or clear cache when the device is locked. You can also opt in to receive notifications for battery drain and heating as well as choose the type of the battery indicator. Xiaomi Mi MIX is equipped with a 4400 mAh battery (non-removable). Its model is BDMC. The accumulator is coupled with the Quick Charge 3.0 technology and arrives with a 5V/2.5A; 9V/2A; 12V/1.5A fast charger. Below you see a graph that shows the charging time (0-100%) and battery temperature from the beginning to the end of the process. Charging started steadily with a rate of 1% per minute and continued like this till the battery reached 40% of its capacity after 40 minutes. Then the speed increase, but only very slightly, so the following 40% needed 35 minutes. After that the charging speed decreased significantly - 13 minutes from 80% to 90%, and the last 10% to full capacity needed 38 minutes to complete. The total charging time was 2 hours and 5 minutes. At the same time, the temperature of the battery changed proportionally. It started from 30°C and immediately reached 34°C. At 40% of the capacity the battery temperature measured 41°C and continued rising to 43°C (at 70% of the charge). After that point, when the charging speed started slowing down, the temperature started decreasing too. When the process was completed, the battery temperature measured 29°C. We ran the PCMark Work battery test (the two versions) several times, but due to bugs in the app, none of those times the test could be finished.

Final thoughts

Mi MIX is without any doubt the most discussed smartphone of 2016 and will continue to be the most discussed one at least during the first quarter of 2017. It is not the "wow" effect from the big screen or the stunning design that are responsible for this, but the whole concept of combining perfect form and function created to serve people. It is precisely this philosophy that drives innovation and has put Xiaomi in a "riding the wave of momentum" position. Hopefully, it will be backed strongly by the company's participation in the CES 2017 in Las Vegas next month and will serve as a trigger for this Chinese company to turn into a global player in the smartphone market.