Xiaomi Mi Mix 3 5G review: The best-value 5G smartphone?

Last year’s Xiaomi Mi Mix 3 was a competent, mid-priced flagship alternative that ultimately wasn’t quite as good as its biggest rival, the venerable OnePlus 6T. The differences between the two phones were marginal, but the OnePlus 6T’s superior rear camera and less fiddly software edged it slightly closer to a recommendation.

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However, following the arrival of the very first wave of 5G-equipped smartphones in UK shops, the now eight-month-old Mi Mix 3 has returned, but this time with a bit of a facelift. Not only is it Xiaomi’s mid-range handset now more powerful but it has a bigger battery and – most importantly – supports these superior mobile internet speeds.

However, is this super-fast smartphone utopia worth paying extra for at this early stage?

Buy Xiaomi Mi Mix 3 5G

Xiaomi Mi Mix 3 5G review: What you need to know

Xiaomi’s 5G handset is practically identical to the phone that came before it, but there are a few key differences. The Mi Mix 3 5G is powered by Qualcomm’s most up-to-date silicon, the Snapdragon 855, rather than the last-gen 845. Not only does this chipset work in tandem with the new X50 Modem to access the 5G network, but it also provides substantial performance improvements. The phone is also fitted with a larger 3,800mAh capacity battery.

Other than the new processor, bigger battery and 5G capabilities, everything else remains unchanged. It has a 6.39in screen at a resolution of 2,340 x 1,080 and a triple-camera array on the back. It runs Android 9 Pie with the firm’s own MIUI 10 software overlay placed on top. The clever sliding mechanism for the selfie camera makes another appearance, too.

Xiaomi Mi Mix 3 5G review: Price and competition

Because 5G is still in its infancy, the barrier for entry is alarmingly high. The Mii Mix 3 5G is exclusive to Vodafone’s mobile network in the UK – it can’t be purchased SIM-free – and 24-month 5G contracts start at £56 a month with an upfront cost of £29.

This is for Vodafone’s ‘Unlimited Lite’ package, which is capped at 3G-like download speeds of only 2Mbits/sec; something that softens the allure of an expensive 5G phone contract. The next tier, which costs £59 a month, is also restricted to a nearly pointless 10Mbits/sec.

If you want to access the fastest possible speeds of up to 2Gbits/sec, then you should expect to pay £63 a month with the same upfront cost on the firm’s ‘Unlimited Max’ plan. If you do the sums, that means the Xiaomi Mi Mix 3 5G will cost a wallet-wilting £1,541 by the time your 24-month contract comes to a close.

That might sound expensive (and it is) but this is actually the cheapest unlimited data 5G contract on the market. The only other phone on Vodafone’s list is the Samsung Galaxy S10 5G, which costs a total of £1,925 on the same plan.

Of course, Vodafone isn’t the only 5G-capable mobile network in the UK. EE was the first to cut the 5G ribbon and its list of phones is much longer, including premium handsets such as the OnePlus 7 Pro 5G, Oppo Reno 5G and LG V50 ThinQ 5G. EE doesn’t currently offer unlimited 5G data contracts, instead limiting its service to capped 10GB, 30GB, 60GB and 120GB plans that range from £54 to £89 per month.

I’m yet to test EE’s 5G coverage for a like-for-like speed and latency comparison, but at the time of writing Vodafone’s service appears to offer much better value for money. Disregarding the two entry-level 5G contracts with their restricted speeds, Vodafone is the only UK network to offer truly unlimited 5G data plans that actually work out cheaper than EE’s data-capped contracts.

Xiaomi Mi Mix 3 5G review: 5G performance and analysis

This is the first commercially available 5G smartphone we’ve reviewed so far – the first among many launching this year – and like all the others, the Mi Mix 3 uses the Qualcomm Snapdragon 855 chipset for 5G connectivity.

The way this works is that the phone’s bundled X50 modem is able to connect to sub-6GHz 5G networks with download speeds up to 2Gbits/sec. This low-band frequency isn’t nearly as impressive as the sort of speeds that are expected to be delivered by millimetre wave (mmWave) 5G frequencies in the coming years, but the technology is certainly off to a promising start.

If you’re used to sluggish downloads over a 4G network, then these sub-6GHz speeds are a big improvement. In our testing in various 5G locations around central London, the Mi Mix 3 was able to download the entire 586MB 4K Blade Runner 2049 package on Prime Video in 30 seconds. Comparatively, its 4G network only managed 69MB.

Vodafone’s 5G coverage isn’t entirely reliable, though, at least when it came to our testing during a rainy afternoon in London. I used Ookla’s SpeedTest app to measure average speeds and latency in three separate London locations: Soho Square, Howick Place and St James’ Park. In the latter I couldn’t find a 5G signal at all, even after almost an hour of searching.

Performance varied quite a bit, reaching lows of 48Mbits/sec and highs of 231Mbits/sec. I never managed to hit anywhere close to the promised 2Gbits/sec, although my colleague at our sister publication, IT Pro, reached a record high of 450Mbits/sec in Birmingham. Average latency wasn’t too shabby at 20ms, though, and you could say the same for the average upload speed of 21Mbits/sec.

Still, you can’t shine too harsh a light on 5G as a whole, especially as coverage and speeds will (hopefully) mature as time goes on. It’s just a shame that we don’t seem to be getting the speeds we were hoping for at launch – and doubly so when you factor in how much these 5G contracts cost.

Vodafone’s 5G network is currently live (in some capacity) in Birmingham, Bristol, Cardiff, Glasgow, Liverpool, London and Manchester, with a total of 19 locations expected by the end of 2019. You can check if you get 5G in your area by using Vodafone’s network status tool.

Xiaomi Mi Mix 3 5G review: Performance and battery life improvements

Another key part of the attraction of the Xiaomi Mi Mix 3 5G is that it offers better CPU and gaming performance over its non-5G-brandishing counterpart. The 5G variant has a Qualcomm Snapdragon 855 inside, which is built using a slightly tweaked, more power-efficient internal architecture over last year’s Snapdragon 845. This is accompanied by 6GB of RAM and 128GB of storage.

In testing, we found that it outperformed the original phone’s speeds by almost 50%. Performance is pretty much unbeatable, with only marginal differences between its results and those of contemporaries such as the OnePlus 7 Pro, Oppo Reno 10x Zoom and Sony Xperia 1.

Finally, the Mi Mix 3 5G has a bigger capacity battery at 3,800mAh, compared to the original model’s 3,200mAh unit. Battery life is much improved, as you might expect, reaching a total of 22hrs 50mins before needing to recharge. 5G doesn’t seem to negatively impact the phone’s overall battery life either, dropping only 20% after two-and-a-half hour’s worth of heavy use.

Xiaomi Mi Mix 3 5G review: Everything else

Other than the new processor, X50 5G modem and the bigger battery, the 5G variant is much the same as the original Mi Mix 3. This is a phone with a large 6.39in 1,080 x 2,340 notch-less AMOLED display and a sliding mechanism that hides the selfie camera away behind the display when it’s not being used.

Unsurprisingly, our technical display tests recorded identical results to the regular model. Colour accuracy is excellent, with an average Delta E of 1.65, covering 100% of the sRGB colour gamut. Readability is top-notch too, with a perfect contrast ratio of Infinity:1 and a maximum screen brightness of 554cd/m2 with the phone’s auto-brightness setting switched on.

It’s also a great-looking phone and takes outstanding pictures, courtesy of its dual rear 12-megapixel cameras and 24-megapixel/2-megapixel selfie cameras. Image quality isn’t quite a match for the Huawei P30 Pro, nor does it match the new Xiaomi Mi 9 and its 48-megapixel triple camera. All the same, it’s a pretty darned good output for a phone at this price.

Xiaomi Mi Mix 3 5G review: Verdict

So, should you really buy into the 5G revolution at this early stage? Despite what those adverts on the Tube would have you believe, there simply aren’t enough benefits in the souped-up mobile network to recommend picking up a lengthy (and ultimately expensive) 5G contract at this time.

Buy Xiaomi Mi Mix 3 5G

Like its 4G-only counterpart, the Mi Mix 3 5G remains a solid smartphone that’s more than worthy of a decent score. It’s just such a shame that 5G’s early days aren’t nearly as impressive.