The Xiaomi Mix 4 series has been making waves since its first iteration. The aim behind the Xiaomi Mix 4 series has always been to use as many screens as possible. The first two models moved the camera into the chin under the screen, the Mi Mix 3 could be slid open to reveal the camera. With the Mi Mix 4, a new solution is now being devised to elegantly hide the front camera. But stop for now! Xiaomi has gotten rid of the “Mi” suffix, so the Xiaomi Mi Mix 3 is now followed by the Xiaomi Mix 4 or Mi Mix 4. Now that that’s clear, let’s start the test!
The second feature of the Xiaomi Mix 4 series has always been the outstanding workmanship of the devices. The Mix 4 is no exception but rather goes one better. The keyword here is ceramics. Xiaomi Mix 4 is one of the few manufacturers that use this material for their smartphones. Ceramic promises a significantly higher resistance with a similar appearance to the glass. I can confirm that. After two weeks of testing without a case, the device didn’t get a hint of a scratch. However, ceramic is not superior in terms of resistance to breakage, so you should be careful here. The Xiaomi Mix 4 is also not lightweight. Although Xiaomi speaks of weight savings of 30%, the device still weighs 225 grams and is noticeably heavy in the hand during longer sessions. With dimensions of 162.7 x 75.4 x 8 millimeters, the Xiaomi Mix 4 is large, but still really thin.
As has become fashionable in recent years, the smartphone boasts a gigantic camera hill. This stands out from the device as a black rectangle and protrudes by around 5 millimeters. There are three sensors inside, which I don’t think are really nicely arranged. The main camera gets a huge frame, and the ultra-wide-angle camera next to it almost disappears into the device. A periscope lens sits asymmetrically under the main camera. Everything seems somehow gigantic and loveless. In addition, the smartphone wobbles on smooth surfaces like no other.
The processing of the ceramic is really strong from Xiaomi. The manufacturer manages to pull the material right up to the display so that a metal frame is no longer necessary. So we are dealing with a unibody ceramic case here. Considering how difficult it is to machine ceramics, it’s a top-notch performance from Xiaomi. The Mix 4’s finish is polished to a mirror finish, making the phone susceptible to fingerprints. We tested the black version of the smartphone; alternatively, the Mix 4 is also available in gray or white. The feel of the back is extremely smooth and I was concerned that the device would slip out of my hand. Thankfully, that never became a reality. However, it was often observed how the smartphone began to slip on smooth surfaces even at a slight incline. If you want to prevent this, you can use the protective silicone cover provided by Xiaomi, but somehow it’s also a shame to use one of the few ceramic smartphones in the world only to then slam a cover on it.
Xiaomi mix 4 installs the volume rocker and power button on the right side of the Mi Mix 4. Both buttons are easy to reach with one hand. The Mix 4 can be charged via a USB-C port on the underside. Unfortunately, it is only a 2.0 socket. The loud and clear sound of the hybrid stereo speakers is much more pleasing (auricle is used as a second speaker). Only at very high volumes do the highs rattle a bit, but there is a hint of bass in return. Overall, the sound is really good for a smartphone. As usual, the Xiaomi Mix 4 gets along with two Nano-SIM cards and cannot be expanded with a MicroSD card. On the top of the Mix 4, we find an infrared transmitter and a second microphone, the SIM slot is on the bottom of the device. The Mix 4 can be unlocked with face recognition via the camera or by fingerprint. Since the camera quality of the front camera is rather mediocre, we recommend the fingerprint sensor. It works quickly and reliably and takes you to the home screen in less than a second.
The Xiaomi Mix 4 has become an impressive phone. This is mainly due to the sheer size of the device and the huge camera hill. The ceramic back is scratch-resistant and has no knots, and it doesn’t need a separate metal frame. As a result, the device looks like it is made of one piece and is great to look at. Unless you can get at it with your fingers because then you leave marks immediately. Furthermore, the camera hill, which is too large, interrupts the flowing design and undeservedly draws all the attention to itself, Xiaomi Mix 4 could have liked to have held back a little more here.
After the excursion to high-resolution displays with the Mi 11 series, Xiaomi Mix 4 returns to the good old Full HD display for the Mix 4. That means 2400 x 1080 pixels on a 6.67-inch screen diagonal and a razor-sharp image with 394 pixels per inch. As befits a flagship, the Mix 4 comes with the dream combination of AMOLED + 120Hz. This ensures an all-around successful viewing experience. All animations are super smooth, scrolling through the browser or feed is just that much smoother. In addition, the great AMOLED-typical high contrasts and Xiaomi’s almost limitless setting options for color rendering, that’s how it has to be! Of course, there is also a mode for intelligently adjusting the Hertz number. This reduces the number of Hertz as soon as the display does not register a touch for a longer period of time.
Fortunately, the Xiaomi Mix 4 Widevine L1 is certified and can therefore easily playback streaming content in HD. There are also certifications for HDR10+ and Dolby Vision. Handy for YouTube or Netflix content that uses one of the standards. A small drop of bitterness for many may be the curvature at the edge of the display. The curved effect sometimes leads to incorrectly recognized inputs, but it simply looks chic. You can also switch the area on the edge of the display to be touch-insensitive in the settings, which helps a lot.
As we are used to from Xiaomi, the Mix 4 comes with a lot of features to regulate the display. The color reproduction can be freely calibrated, and there is also a dark or reading mode that can be terminated. Xiaomi’s image beautifier “AI Image engine” is also back, as is DC dimming. An always-on display (AOD) is of course also part of the game. If you want, you can schedule it, make it extensive and switch it off automatically in battery saver mode. As in the Mi 11, the Xiaomi Mix 4 comes with a very high sampling rate of 480Hz. The panel is protected by Gorilla Glass Victus, Corning’s strongest protective glass to date. In terms of brightness, Mix 4 achieves average values. The panel comes to 800 lux manually. There is no boost in automatic mode. The reason for this is probably the under-display camera, which brings us to the next topic:
Let’s get to the selling point of the Xiaomi Mix 4: the under-display camera. Now that pop-up cameras have gone out of fashion again, we’ve been wondering for a long time how Xiaomi Mix 4 intends to hide the front camera in the Mix 4. We now know the answer. The camera disappears under the display! So not under the display, off in the chin, like in Mix 1, but under the display glass. This results in a display without interruptions, no moving parts, and no awkward posture for selfies!
We already know the attempt at a UDC (=Under Display Camera) from a number of devices, such as the ZTE Axon series. Unfortunately, this has hardly been convincing so far, somehow the camera was always visible. We approached Mix 4 with corresponding skepticism. But it does its thing really, really well. I would say surprisingly well. In everyday use, the camera is actually barely visible.
This applies to the system, videos, and gaming as well as all other apps. If you compare that to the first UDCs, where pulling down the status bar made the camera painfully noticeable, that’s a giant step! Sure, the camera isn’t entirely invisible. This is noticeable in brilliantly bright or pitch-dark surroundings. In bright sunshine and the display is as bright as possible, the camera can appear as a slightly less bright spot at the top of the display. In the dark, the circle is slightly brighter than the rest of the display.
At no point is the UDC more conspicuous than a normal punch hole in the display. This is largely due to the fact that the sharpness of the display above the camera is as good as anywhere else. We know that from ZTE quite differently. In this way, the area does not attract negative attention, even if the displayed content is movable. Great praise to Xiaomi, for me personally this is the first approach that credibly assures me that smartphones won’t have to get by with Notch forever!
Two points to the UDC. By default, Xiaomi applies a foil to the Xiaomi Mix 4. It has a recess above the front camera. So there’s a hole in the film where you’d normally expect a camera, but there isn’t now. This hole is more noticeable than the UDC. So just take the foil off, you won’t regret it! Second, in strong sunshine, Xiaomi fades in a small sun over the UDC. This should probably hide the fact that the display is not quite as bright at this point. This is unnecessary in my opinion and rather draws attention to the spot.
For me personally, the Mix 4’s display is the best mobile phone display I’ve ever seen. We now know AMOLED and 120Hz from many devices and we have already praised Xiaomi’s extensive setting options here enough. But the under-display camera just takes it to a whole new level. The only point of criticism is the lack of auto mode for the refresh rate and possibly the curved display.
As befits a smartphone from the Mix series, the Mix 4 is equipped with a top-class SoC. With the Snapdragon 888 Plus, a higher clocked version of the well-known flagship processor SD888 is used. The octa-core processor has the following cores and clock speeds: 1x Cortex-X1 with 2.995 GHz 3x Cortex-A782.4 with 2.4 GHz 4x Cortex-A55 with 1.8 GHz Adreno 660 graphics unit.
At least that’s how it looks in the first run. We ran the mix through five passes of Antutu 4 times. Well, we didn’t, because the third round was the end. MIUI exits Antutu with the message that the device is about to overheat. We rarely had that. In the Throttle Test, a CPU-heavy benchmark, the Mix 4 fares much better. At the end of the test, the processor is still running at over ninety percent. This is so above average that we started to ponder a bit. Turns out that our Mix 4 throttled the clock rate to 2.15GHz in the benchmark.
It’s hardly surprising that the SoC spits out little heat at just around 70% of its clock speed. We are disappointed that after OnePlus, Xiaomi Mix 4 is now also using such tricks. Some people may now say that benchmarks have little to do with reality anyway. We basically agree with that, but unfortunately, the heat problems are also noticeable when gaming. After a quarter of an hour in Genshin Impact, COD Mobile, or Asphalt 9, the Xiaomi Mix 4 is at least 40 degrees Celsius according to the Power Monitor. If you play longer, the temperatures level off at 44 degrees Celsius. Since it is already uncomfortable without a cover.
However, the Mi Mix 4 again cuts an excellent figure in the GPU-heavy wildlife stress test. It was even worse in ARC: Survival evolved. After 30 minutes on the highest settings, the game is closed by the system at a temperature of 50 degrees Celsius, and there is a risk of overheating again. Accordingly, we cannot recommend the Mix 4 as a gaming phone. As bad as the heat issues are for gamers, they’re not a hint of a problem in everyday use. Together with the 12GB LPDDR5 RAM and 512GB UFS3.1 of our test model, the SD 888 Plus sprints through the system.
It’s really fun, especially in combination with the high refresh rate. Animations can hardly be smoother, you almost fly through the system. The fast memory does the rest to make the Mix 4 a really fast smartphone. With a read/write speed of 1610/735 MB/s, every installation is completed in a blink of an eye, the LPDDR5 RAM achieves 38 GB/s. That’s just fun, even if we’ve seen faster speeds from Xiaomi. The system of the Xiaomi Mix 4 is intended as a device for China. It is therefore delivered with a Chinese version of MIUI by default and does not have the Google Playstore or other Google services in it. Otherwise, the system looks almost exactly like the usual global MIUI. Anyone who has ever used a Xiaomi Mix 4 smartphone will have no problems with the Mix 4. The instructions for installing the Playstore can be found here: Install Xiaomi Mix 4 Playstore.
Once the Playstore is installed, it is best to delete all the bloatware. Unfortunately, some of that is on Mix 4. We counted a total of 24 apps. Luckily, you can easily uninstall them. Then quickly install the remaining Google apps and almost everything is as usual from the global version. Thanks to Widevine L1, you can easily stream content in HD, and if you pass the safety check, you won’t have any problems using Google services without restrictions. Well, it is something else with Chinese MIUI, because the Xiaomi Mix 4 can only be used in English, German is not available as a language.
The entire system is in good English, MIUI only sends you a few push messages in Chinese. I actually had no problem at all with advertising, there simply wasn’t any. If this is different for you, you will find instructions on how to remove it in this article. Otherwise, I noticed two other points when using the Mix 4. Xiaomi advertises cooperation with three keyboard app providers on its website. Together they have developed a particularly secure keyboard. The consequence of this is that you can install so many other keyboards, Xiaomi Mix 4 turns them all off again after restarting the device and switches to the native keyboard, annoying.
The next point is Xiaomi’s aggressive dark mode. I just can’t warm to it. It’s great in the system and I really enjoy using it. But what I don’t like is that MIUI works with a kind of color inversion in all apps to adapt them to the system. Often looks stupid and then you have to manually exclude the apps from dark mode again, annoying. The last point is missing Google Discover. The page to the left of the home screen, which should actually display a personalized Google News Feed, displays a Chinese equivalent on the Xiaomi Mix 4. That’s not really helpful. It can be turned off, but you need a different launcher for Google Discover. Or you do what we strongly recommend to everyone with Mix 4 and install the Xiaomi.Eu ROM. You can find the instructions here.
The triple camera of the Xiaomi Mix 4 consists of an ultra-wide-angle camera, a 5x periscope camera, and the main camera. Except for the periscope camera, the setup strongly reminds us of the Xiaomi Mi 11. However, the frame in which the three cameras are installed is much more conspicuous than in the Mi 11. For me personally, this is clearly too much. But let’s get to the really important thing, here are the specs of the cameras: