If you want top-end hardware in the cheapest possible smartphone, you should look no further than Xiaomi’s Mi line. Last year’s Mi 5 packed all the best hardware, including top-end Qualcomm Snapdragon SoCs and high quality cameras, in a sub-$400 package, undercutting pretty much every device on the market, including the OnePlus 3.
In 2017, Xiaomi has updated their flagship product line with the Mi 6, and the story remains largely the same. You’ll be getting top-end hardware – including a Snapdragon 835 SoC, 6GB of RAM, 64GB of internal storage and a dual 12-megapixel camera solution – in a package that costs around $430 when imported. With phones like the Galaxy S8 costing over $700, and the LG G6 setting you back $550 for largely last-generation hardware, the Xiaomi Mi 6 is an absolute bargain at this price point.
The only downside to purchasing the Xiaomi Mi 6 is, as with all Xiaomi devices, its lack of availability in Western markets. That didn’t stop us from obtaining one, though: Gearbest will happily ship one anywhere in the world for a very competitive price.
Let’s talk about the design of the Xiaomi Mi 6, because I know the company has spent a lot of effort creating what they describe as a premium chassis. In fact, Xiaomi was quick to inform everyone during their announcement presser that the Mi 6’s stainless steel construction requires a 50-step manufacturing process and over 270 individual operations. This sounds like a fair bit of work, and the fact the chassis is stainless steel presents a point of difference compared to other phones that tend to use aluminium.
Unfortunately for users, the Mi 6 is barely a stainless steel phone at all. The entire front and rear panels are constructed from glass, with only the edges giving you that metal look. The build quality here is fantastic, with extremely swooshable glass and a near seamless transition from glass to metal edges. Xiaomi has also ensured that every element is symmetrically aligned, which is a touch of polish not often seen among Android OEMs.
While the build quality is great, I’m not a fan of the general Mi 6 design for several reasons.
First, the Mi 6 is ridiculously slippery. The glass back panel repels your fingers in a similar way to the Galaxy S8, while the metal edges appear to be coated with the same glossy finish as the rear. At times, the Mi 6 can be a difficult phone to hold, though its relatively compact 5.2-inch size does help somewhat. The Galaxy S8 is a more slippery phone due to its slim edges, but the Mi 6 comes in a close second.
Luckily for buyers here, only the rear glass panel is curved to either edge, and even then, the curve is minimal compared to the Galaxy S8. The front panel is entirely flat, which protects the display from shattering when you drop it on an edge. Having glass on either side is always a bit of a risk, though I suspect the Mi 6 won’t be as fragile as the Galaxy S8 due to its more sensible display design.
One of the other issues with the Mi 6’s design is just how glossy it is. I received a black model to review, and this variant attracts noticeable fingerprints like nothing else. You’ll be cleaning this phone 10-15 times a day if you want it free from fingerprints, as it gathers grime literally as soon as you touch it. I tend to think glossy finishes give expensive phones a cheap-ish feel, and while I appreciate the minimal style of the Mi 6, it doesn’t strike me as a ‘premium’ build.
The premium design issue is compounded by the enormous bezels above and below the display.
Just before I received the Xiaomi Mi 6, I was testing out the LG G6 and Samsung Galaxy S8+, both of which pack extended displays and reduced bezels in their premium bodies. Obviously the Mi 6 is a far cheaper device, but it’s hard not to notice the overwhelming last-generation bezels on this handset.
Part of the reason this phone’s bezels are so large is to accommodate the fingerprint sensor below the display. Like most phones these days, the Mi 6 fingerprint sensor works extremely well, and functions as a home button without any struggle. Flanking the sensor are capacitive navigation buttons on either side, which are configured to back and the app switcher. Rather than printing specific icons on the phone for these functions, Xiaomi has just used dots as you can switch the order in the software.
Xiaomi joins the list of companies, which include Apple, HTC and Motorola, that have decided to remove the headphone jack from their flagship phone in favor of just USB Type-C. I hate everything about this. There is no advantage to having just a USB-C port compared to having a USB-C port and a 3.5mm headphone jack. Instead all we’re left with is pain – dongle pain – whenever we want to use headphones with a standard 3.5mm jack. At least Xiaomi includes a dongle in the box.
The Mi 6 implements stereo audio by combining the in-call speaker above the display, and a speaker along the bottom edge. Stereo audio is always better than mono on smartphones, so I appreciate the inclusion here. Dual front facing speakers are typically the best implementation, as the speaker along the edge can get blocked and tends to produce unbalanced sound. However, with the I’ll take any form of stereo audio.
Xiaomi claims the Mi 6 is “splash proof”, although the company did not provide an IP rating, so it’s hard to say just how splash proof it really is. Clearly it isn’t water resistant, otherwise Xiaomi would boast about this capability, though I suspect its splash proof in the sense that it’ll be fine if you spill some water on it. I wouldn’t recommend gaming on the Mi 6 in the shower or dropping it in a bath.
The Mi 6 includes a SIM card tray on the left edge that supports two SIMs, however there is no microSD expansion available here. This is the same as with the Mi 5, however this time, 64 GB of storage is standard rather than 32 GB. I tend to find 64 GB is perfectly fine for most users without expandable storage, though expandable storage is always a nice feature to have. For those that need more space, Xiaomi does provide a 128 GB option for around $70 extra.
The Mi 6 packs a 5.15-inch IPS LCD with a resolution of 1920 x 1080. This is a fairly modest display by today’s flagship smartphone standards, as you can easily get a 1080p IPS in an entry-level phone these days with most companies opting for 1440p screens instead. However, Xiaomi clearly feels 1080p is perfectly adequate for their flagship, and they’d prefer the increased performance and battery life afforded by the lower resolution.
At 428 PPI, the Mi 6 display still looks great despite its lower resolution. Naturally it’s not as crisp as top-end 1440p LCDs, however the LCD used here is still very sharp for viewing text and imagery, while the near-indistinguishable gap between fingertip and LCD provides a lifelike experience. Viewing angles here are also very good for this type of technology, with minimal color and luminance shift at off angles.
Xiaomi claims this LCD is capable of 600 nits of peak brightness, and I easily validated this claim during my testing (in fact the screen is slightly brighter than this). Xiaomi also uses some marketing fluff about “negative LCD displays”, whatever that means, to describe the excellent contrast ratio of this panel. Again, the Mi 6 performs extremely well for an LCD in this regard, almost topping our charts.
For some bizarre reason, Xiaomi talks about the Mi 6’s NTSC color gamut reproduction, despite the fact NTSC isn’t used in Android and really no one across the industry uses it. The good news is this display performs well in color performance out of the box, covering 99.9% of the sRGB spectrum with surprisingly solid default accuracy. The screen is a bit too cool by default, however it comfortably beats most other high-end smartphones in accuracy. And the display still looks fantastic while doing so.
Even better, Xiaomi includes a display mode called ‘standard’ (which isn’t the default mode, by the way) that improves upon the already solid out-of-box performance. The main advantage of this mode is how it corrects the white balance to essentially dead accurate, which in turn improves greyscale performance. Color performance isn’t impacted as significantly, though in this mode the Mi 6 still sits right near the top of our accuracy charts.
From this perspective, the Mi 6 is a very solid option for those that need a near color-accurate smartphone display, or just don’t want something ridiculously oversaturated. It’s one of the best and brightest LCDs on the market; the only major downside being its lower resolution than some competitors.
Hardware Overview and System Performance
The Xiaomi Mi 6 is the first device I’ve received to review that’s powered by a Qualcomm Snapdragon 835 SoC, the current-generation flagship in Qualcomm’s line-up. So let’s talk a little about the new SoC and what it brings to smartphones.
In the CPU department, we’re looking at an upgrade from a 2+2 quad-core design in the Snapdragon 820, to a 4+4 octa-core design using new Kryo 280 CPU cores. The new Kryo 280 is not a derivative of the old Kryo core from the S820, instead being derived from the ARM Cortex-A73 which should bring improved IPC relative to last year’s core design. As for clock speeds, we’re seeing 2.45 GHz on the high-performance cluster, and 1.9 GHz on the efficient cluster.
The GPU has been upgraded from an Adreno 530 at 653 MHz (in the S821) to an Adreno 540 at 710 MHz. Most of the performance improvement over last year’s SoC comes from the increased clock speed, however Qualcomm has tweaked some aspects to the ALU which improves performance further. The company claims a 25 percent average gain over the S820 in GPU performance.
We’re also seeing a Hexagon 682 DSP, support for 10-bit 4K HEVC encoding and decoding at 60 FPS, support for UFS 2.1 storage, support for Qualcomm Quick Charge 4.0, and an LPDDR4X memory controller providing 29.8 GB/s of bandwidth. The manufacturing process used has also shrunk, from 14nm to Samsung’s 10nm LPE.
Connectivity-wise the Snapdragon 835 supports a wide range of connectivity, and most of it has been implemented in the Xiaomi Mi 6. We’re seeing Category 16 LTE downstream and Category 13 upstream for 1000/150 Mbit/s throughput respectively, thanks to the integrated X16 LTE modem. There’s also Wi-Fi 802.11a/b/g/n/ac support with 2x2 MIMO and Bluetooth 5.0, plus NFC in the Mi 6.
The Mi 6 includes a ludicrous 6 GB of RAM, which is mostly unnecessary for a smartphone. Extra RAM means more apps can be stored in memory for quick re-opening, though for the most part I didn’t notice a significant performance difference in app loading relative to devices with 4 GB of RAM in day to day tasks. There’s also either 64 or 128 GB of internal NAND depending on how much you want to pay.
In general, the Xiaomi Mi 6 is an incredibly fast phone to use, and that’s partly due to the very short animations Xiaomi has implemented. App loading is still extremely quick though, and the S835 helps make this phone feel snappy throughout the OS and apps.
Looking at benchmark data, what we’re seeing is a handy 31 percent lead in CPU performance on average over the Snapdragon 821 in the LG G6. When comparing the S835 to the lower-clocked Snapdragon 820, that lead extends to a commendable 47 percent. Of course, the S835 does include an extra four cores, but most Android applications only use a few threads and this is generally reflected across our benchmark suite.
Compared to other modern SoC platforms, the Snapdragon 835 comfortably beats the Exynos 8895 in the Samsung Galaxy S8 (Exynos variants) by 24 percent on average in CPU tests. The Exynos 8895 uses Samsung’s own Exynos M2 cores, and four of them clocked at 2.3 GHz in the high-performance cluster. The S835 is clocked just seven percent higher, so these gains come mostly from architectural differences; Qualcomm’s CPU designs tend to be pretty solid.
Compared to the Kirin 960, which uses standard Cortex-A73 cores at up to 2.36 GHz, the S835 CPU is 13 percent faster on average. The Kryo 280 cores are clocked around four percent higher, so again we’re seeing Qualcomm’s design efficiencies here.
Graphics, Throttling and Storage Performance
The GPU in the S835 has also received a healthy boost relative to the S821. We’re seeing typical raw performance gains of around 27 to 37 percent in offscreen GPU benchmarks, which is a handy gain that falls in line with what we’re seeing on the CPU side. With screens now extending beyond 2560 x 1440, the GPU is more than capable of handling those extra pixels (not that the Mi 6 uses a screen of that resolution).
The comparison between the Adreno 540 and the Exynos 8895’s Mali-G71 MP20 is rather interesting, as both GPUs trade blows in offscreen benchmarks. The Adreno 540 is anywhere from 11 percent faster to 8 percent slower depending on the offscreen test, while in other benchmarks like Basemark, the Adreno GPU falls well behind. Neither GPU is slow, though, and thanks to the Mi 6’s 1080p resolution we’re seeing pretty large onscreen performance gains over 1440p displays.
And finally, compared to the Kirin 960’s GPU, the Adreno 540 puts in a crushing performance to beat the G71 MP8 by upwards of 30 percent.
Bad news, everyone. The Qualcomm Snapdragon 835 in the Xiaomi Mi 6 throttles significantly under a GPU-heavy workload. In GFXBench’s Manhattan 3.1 test, the Mi 6 gets cut down by 43 percent after 25 minutes, matching the level of throttling seen by the Exynos variant of the Galaxy S8+. And this is even considering the lower resolution of the Mi 6’s display. Heavy throttling is always disappointing to see.
Storage performance follows the trend of the Galaxy S8+, in fact I wouldn’t be surprised if both phones use the same internal storage. The Xiaomi Mi 6 exhibits fantastic sequential performance, however it suffers in random performance compared to the best smartphones on the market. Still, the NAND performance in general here is pretty good.
The camera is one of the biggest areas to receive an upgrade in the Xiaomi Mi 6. We’re seeing a dual rear sensor implementation similar to the iPhone 7 Plus here, with a normal wide angle camera paired with a 2x zoom camera. I tend to think this is one of the better dual camera solutions, as the zoom does come in handy if you want extra close-up detail.
The actual hardware we’re seeing is two 12-megapixel sensors on the rear, however the sensors aren’t identical. The wide-angle camera gets a Sony IMX386 1/2.9” sensor with 1.25µm pixels, paired with a 27mm f/1.8 lens with optical image stabilization. The zoom camera has 1.0µm pixels, which equates to a 1/3.6” sensor, with a 52mm f/2.6 lens, meaning the actual zoom factor from wide to secondary camera is 1.93x.
2x zoom camera
There are some interesting things to note about this camera setup. Firstly, the zoom camera does not have OIS, which is arguably more useful on this camera as it is more prone to motion blur from a shaky hand. It seems there is simply no room (or budget) to include both a 52mm lens and OIS in the same module. It’s also worth noting the zoom camera has less light gathering ability, as its lens is a full stop narrower and the sensor’s pixels are smaller.
The front-facing camera is an 8-megapixel native 16:9 sensor paired with an f/2.2 lens. Video capture goes up to 4K at 30 frames per second on the rear camera, while the front camera is capable of 1080p video capture (despite having enough resolution for 4K).
The quality of the rear cameras on the Mi 6 are… okay. Up against the best cameras at the top of the tree – namely the Galaxy S8, Pixel XL, LG G6 and iPhone 7 Plus – the Mi 6 doesn’t compete strongly as these cameras focus heavily on image post processing. The Mi 6 tends to use more stock-quality processing, which leads to weaker results in general.
Outdoors, the Mi 6 is a mix of great photos and surprisingly poor photos. When the sun is shining, either camera produces great results, with saturated colors and decent contrast. However, if it’s even slightly cloudy, the Mi 6 tends to make images way too underexposed, leading to dark and unimpressive photos. Other flagships perform better across the board when outdoors, which is usually the strong point of post smartphone cameras.
Indoors, the Mi 6 again is a reasonable but not fantastic performer. The main 12-megapixel wide-angle camera exposes well and produces photos with respectable levels of dynamic range and color, however fine detail tends to suffer indoors due to post-processing artefacts. The Mi 6 is better than average in these conditions, and should suffice for most users.
Considering the Mi 6 boasts 1.25µm sensor pixels, an f/1.8 lens on its wide camera, and optical image stabilization I was expecting better results in low light. Images are bright and vibrant for the most part, however detail isn’t great and it takes a steady hand to get a blur-free result, even with OIS. Perhaps the OIS module Xiaomi uses here isn’t very effective.
Let’s talk about some of the oddities of the Mi 6 camera. To start with, the camera application doesn’t support automatic HDR, instead opting for a toggle in the main interface. My recommendation is to always leave the HDR mode on, as it tends to produce far better dynamic range and color quality, along with a slightly warmer tone. Default dynamic range from the sensor isn’t fantastic, but the HDR mode does a great job of improving results across the board.
I wish Xiaomi used auto HDR because I think average consumers would be much happier with the results captured in this mode, rather than with stock processing. The HDR mode closes the gap between this camera and top-tier smartphone cameras, and it surprised me how many areas of processing are improved with it enabled. Of course, this comes at the expense of camera performance, though the Mi 6 isn’t overly slow with HDR enabled.
Then there’s the zoom camera. You should be aware that even though the toggle between 1x and 2x zoom is always available in the camera interface, the secondary zoom camera is only used in good lighting. This means that if you’re indoors (even in reasonable lighting) or in a darker environment, the 2x zoom toggle will switch to using a digital zoom on the wide camera. Naturally this leads to a serious reduction in detail and generally rubbish results. There’s no way to modify this behavior to force the 2x mode to always use the zoom camera.
Oddly, though, I was more impressed with results from the 2x zoom camera than the wide angle camera in general. Processing between each sensor is slightly different, with the zoom camera exhibiting better metering – images are a warmer, more natural tone – plus superior dynamic range and marginally improved fine detail. Of course you also get the added benefit of the more narrow field of view, which helps create a stronger depth effect for your macro shots. Don’t expect to use this camera to magically see distant objects in great levels of detail, though, as 2x zoom isn’t that much zoom.
I wasn’t hugely impressed with Xiaomi’s camera app, which hides a lot of functions underneath the ‘mode’ selector, including the settings screen. There’s an okay manual mode included, along with a few other somewhat interesting shooting modes like tilt shift. Arguably the best feature is the portrait mode, imitating the same functionality on the iPhone by providing simulated bokeh for your images. When it works, it produces great photos. When it doesn’t work, the fakeness of the effect is very noticeable.
Presumably to save component costs, the Mi 6 is a flagship camera that doesn’t place much emphasis on improving focus or capture times, instead relying on traditional phase detection autofocus rather than having dual focus pixels or laser-assisted autofocus. As I said earlier, the Mi 6 isn’t slow, but it’s not as fast as cameras that have either of those features.
The Xiaomi Mi 6 comes loaded with a 3,350 mAh (12.90 Wh at 3.85V) non-removable lithium-polymer battery, which is a moderate upgrade on the 3,000 mAh battery in the Mi 5. This phone has a number of battery-friendly features up its sleeve, including the 10nm Snapdragon 835 SoC and the lower-than-flagship 1080p display resolution.
It’s pleasing to see most of Xiaomi’s design choices paying off here, leading to better-than-average battery life. This smartphone isn’t going to top the performance charts, currently occupied by the Samsung Galaxy S8+, but it falls somewhere around the Pixel XL, which is a solid result. The Mi 6 also performs exceptionally well in PCMark, which is no doubt due to the Snapdragon 835’s improved efficiency.
Perhaps the best aspect to the Mi 6’s battery life is that it provides very good battery life for its size. Handsets with larger displays, like the Galaxy S8+ and Pixel XL, tend to have better battery life as there is more internal space for a battery. However the 5.2-inch Mi 6 performs around the same mark as these larger handsets, while outperforming devices like the LG G6, Huawei P9 and OnePlus 3.
Xiaomi’s software has been steadily improving over the last few years, where it’s now at a point where people outside China can comfortably use the handset without getting frustrated. Unlike some Xiaomi devices I’ve reviewed in the past, the Mi 6 comes with perfect English translations across the board and Google integration straight out of the box. No having to download a dodgy Google installer app here.
The Mi 6 still uses MIUI, which is Xiaomi’s custom skin now in version 8.2, sitting atop Android 7.1.1. My review device had the May security patches installed and I did receive a couple of updates during the review period, so there might be some hope that Xiaomi will continue to support this device in the future. That said, their track record isn’t impressive in this regard, so I wouldn’t count on it.
The general style of MIUI hasn’t changed much from what I used last year. It’s a heavy skin in the sense that nearly every aspect of stock Android has been visually modified, and several features have been added as well. This is all part of the company’s efforts to stand out in the crowded Android market.
Not every addition or change is positive. One example of a baffling regression is the notification pane, which is where Xiaomi has decided to remove most parts of Android 7.1’s notification system in favor of their own implementation. Pretty much every great feature of current-gen Android notifications has been removed in the process, including expanded information and quick actions. I don’t know why any company would consider making these changes, but Xiaomi has.
The notification pane also includes several quick setting toggles and a brightness slider, along with the current weather, which is a handy feature to chuck in there. The settings screen, on the other hand, falls far too close to iOS for my liking, with poor grouping the primary issue here. Many important settings like the one handed mode, the date and language, privacy settings and so forth are hidden behind the ‘additional settings’ submenu, rather than being parted out into more sensible groups. Xiaomi has also changed things up so some settings are harder to find, such as the screen timeout which is now found under lock screen and password not display like practically every other Android handset.
The general visual style of MIUI is okay, and most parts are reasonably consistent across the board. I still prefer the style of stock Android by far, and I feel that Xiaomi should look towards modernizing their skin to make it fall in line with current Google design trends. MIUI doesn’t fit in super well with other Android apps, especially the launcher, which feels very dated in comparison with the modern Google Pixel launcher.
A number of features I would have classed as ‘unique’ about MIUI a few generations ago are now commonplace among Android skins. Full theming support, storage cleaners, and security apps have made their way from Chinese OEMs to widely popular devices like the Galaxy S8. However, I am very impressed with Xiaomi’s battery optimization tool, which allows you to perform several battery-friendly changes with just one click.
MIUI is filled with bloatware and unnecessary applications. For some reason, Xiaomi thinks you need duplicate browser, gallery, mail and music apps on top of the Google-mandated apps. On top of that, tools like the updater and themes app could have been left as settings menu options, while apps like notes, MIUI Forum, WPS Office and the barcode scanner aren’t necessary.
But hey, at least there’s no more random Chinese characters or dodgy app stores to deal with.
Who Is It For?
The most important thing to remember when discussing the Xiaomi Mi 6 is its price. This is a flagship phone, but it won’t set you back $600+ like most other flagship contenders.
Thus the key selling point to the Mi 6 is its hardware. At just over $400, you’re netting yourself a Snapdragon 835, not some lesser-tier mid-range chip. The 835 is the fastest SoC on the market (that’s available to Android OEMs), and provides around 30 percent better performance than the Snapdragon 821. It’s more efficient than before, and highly capable for today’s smartphone applications.
The end result, when paired with a whopping 6GB of RAM and reasonable NAND performance, is a smartphone that’s extremely snappy to use. Xiaomi has also used just a 1080p display here, so graphics performance is superior to many other flagship phones that opt for 1440p instead. If you’re after speed, the Mi 6 is a great option.
The display surprised me a fair bit, considering on paper it seems like just a basic 5.15-inch 1080p LCD. What we’re actually seeing is excellent peak brightness above 600 nits, plus fantastic contrast and great color performance out of the box.
Another very solid aspect of the Mi 6 is battery life. Most smaller phones tend to suffer in the battery department, but this isn’t the case here. The 3,350 mAh battery, efficient SoC and 1080p display combined deliver great battery life out of the box.
The Mi 6 includes a dual camera solution, with one camera providing wide angle shots and the other providing a 2x zoom. I like this sort of camera implementation, and the 2x zoom is useful during everyday photographing, particularly as it produces higher-quality photos in what is a bit of a surprise.
However, in general the Mi 6 camera doesn’t compete strongly with the best smartphone cameras. Image processing isn’t as good, which leads to merely ‘okay’ results in a number of situations. For the price you’re still getting a solid camera solution though.
While Xiaomi’s software has improved drastically over the last two years, it still needs a lot of work to bring it up to the same standard as what Google provides on the Pixel.
It does run the latest version of Android (7.1.1) and there are some neat features, but there’s a lot of unnecessary applications included and several features that are no longer all that unique.
Phone design is perhaps the most subjective area to a smartphone’s overall quality, so I’m sure there are some out there that will appreciate what Xiaomi has done with the Mi 6’s design. I didn’t fall in love with the glass body for several reasons though. The glossy finish to both the glass and metal edges is incredibly slippery and doesn’t execute well to give the phone a premium feel.
Those big bezels above and below the display also look dated in comparison to the Galaxy S8 and LG G6.
The Mi 6 is yet another phone that doesn’t include a headphone jack, which like I've said before is a user hostile decision, and there’s no microSD card slot either. I do appreciate features like stereo speakers and the quick fingerprint sensor.
The Xiaomi Mi 6 is a flagship phone with some outstanding areas and some weak spots. Considering the low price point, the phone still competes well with the best out there. Naturally, if you have $700+ to spend on something like the Galaxy S8 you’ll be getting a better overall package, but the Mi 6 brings great hardware down to a sub-$450 price point, and for some people that’s all you need.
Pros: Top-end performance and hardware at an affordable price point. Fantastic display, even though it’s only 1080p. Great battery life in a compact form factor. Zoom camera adds to the package.
Cons: Slippery, bezel-heavy design didn’t win me over. No headphone jack! Camera output could still use some work.