The Xiaomi Mi 4 features a similar 5" Full HD IPS display to the one we saw on the Mi 3. It has a pixel density of 441ppi, which places it among the best. This time around, the glass covering the display lacks any protection and it might be a good idea to apply a screen protector.
Taking a closer look at it under our digital microscope reveals a standard RGB arrangement of the sub-pixels that make up the Xiaomi Mi 4 LCD panel, much like on the Mi 3.
The display on the Xiaomi Mi 4 has a higher maximum brightness level compared to the one on Xiaomi Mi 3, while retaining the same good contrast and colors. Also compared to the Mi 3, the Mi 4 screen backlight is much more uniform and you can't easily tell the main source of backlight as you could on the Mi 3.
Subjectively, the Mi 4's display tends to produce cooler images, while the colors on the Mi 3 are warmer. Xiaomi is providing options for color temperature and saturation, so you can tweak the display to your liking.
|Display test||50% brightness||100% brightness|
|Black, cd/m2||White, cd/m2||Black, cd/m2||White, cd/m2|
The sunlight legibility has been improved as well and the Xiaomi Mi 4's display performs admirably outdoors and you will be able to see what's happening on the screen even on the brightest day.
The high-sensitivity mode for Glove use is available here much like on the Mi 3, but you probably shouldn't leave that turned on if you don't need it, because it may drain your battery faster.
Finally, there is a way to prevent accidental screen unlocks, while the phone is in your pocket. If enabled, you won't be able to unlock the screen while something is covering the proximity sensor. Again, that would probably take its toll on the battery life.
The Xiaomi Mi 4's controls are pretty much the same as what we found on its Mi 3 predecessor. Almost the entire front is occupied by the 5" display, but its bezels have gotten a lot thinner. Above the screen we find the earpiece, with a couple of sensors and the 8MP selfie camera around.
Xiaomi once again has decided to keep the capacitive controls instead of wasting precious screen real estate. The trio yet again uses the older arrangement with Menu, Home and Back keys.
The microSIM slot is alone on the right and you will need a SIM ejector to pop it out. The right side of the Xiaomi Mi 4 has the metal volume rocker and power/lock key.
As usual, the 3.5mm audio jack is on the top and an IR blaster keeps it company. You have a choice of apps that you can install to make use of the Infrared port for controlling various home appliances such as TVs, media players, air conditioners, etc.
The bottom of the Mi 4 has the microUSB port and a rather big grille hiding the primary microphone and the loudspeaker.
The Xiaomi Mi 4's rear features the 13MP camera lens with F1.8 aperture, which uses the latest generation of Sony sensors. There is a single-LED flash beside it.
The 3,080 mAh battery hides beneath the plastic rear cover. To get to it you need a small suction cup to pull the cover open. The battery beneath it however is not user-replaceable. It's glued to the the phone and we didn't dare put a pressure on removing it in our review unit.
There is no microSD card slot on the Xiaomi Mi 4 either.
Xiaomi has put a 3,080mAh battery inside the Mi 4, a solid enough unit for a 5" device. We ran our battery test and the Xiaomi Mi 4 scored a 68h rating, which means you can count on the battery to last just short of 3 days if you do an hour each of calling, browsing the web and video playback a day.
The Xiaomi Mi 3 was almost there too with a rating of 66h.
Perhaps this is the right place to mention that we didn't like how hot the Xiaomi Mi 4 became with the charger plugged in.
For a more detailed breakdown of the Xiaomi Mi 4 battery performance check out our blogpost.
Our proprietary score also includes a standby battery draw test, which is not featured in our battery test scorecard but is calculated in the total endurance rating.
Our battery testing procedure is described in detail in case you want to learn more about it.
The Xiaomi Mi 4 runs on the capable Snapdragon 801 chipset which is LTE-enabled, unlike the one on the Mi 3. The Mi 4 also offers quad-band GSM connectivity and quad-band 3G connectivity with HSPA support.
The rest of the connectivity features include dual-band Wi-Fi a/b/g/n/ac support and Wi-Fi Direct. There is also support for Bluetooth 4.0, GPS and GLONASS, plus an FM radio.
The IR blaster is located on the top and coupled with the right software, you can use it to operate pretty much any IR remotely controlled home appliance, turning the Xiaomi Mi 4 into a universal remote.
Unlike the Mi 3, there is no NFC connectivity on the Mi 4. It seems the company thinks there are too few users actually using the feature.
A microUSB 2.0 port handles charging and data connections. Media transfer mode is supported for accessing the phone's built-in memory and microSD card over a USB connection.
The microUSB port also supports USB On-the-go for connecting USB peripherals such as pen drives, keyboards or real USB hard drives.
Wireless screen mirroring is available via the Miracast protocol.