The Z5 Premium’s Resolution is Not Always 4K, and That’s a Good Thing

Each resolution upgrade that hits the smartphone industry brings with it a lot of buzz and discussion on both sides, but with each iteration, the conversation seems less polarized. This is because we are admittedly reaching the point where more pixels yields less of a visual advantage, and we passed the threshold of diminishing returns imposed by standards such as “retina” and other PPI counts.

Said PPI counts are influenced by marketing and what not, but the real question now is, is it worth going forward with higher resolutions? There are a number of things that do benefit from them, but they are typically not linked to regular usage. For example, virtual reality headsets don’t have the pixel density for a clearly convincing experience. The companies behind the jumps can also see benefits, if only because of the buzzword marketing that comes with each new prefix. Now we are making a new yet expected jump, and most people don’t seem to want it.

The Xperia Z5 Premium brings a 4K IPS LCD panel, and from what we gather, it’s a little bit atypical in terms of sub-pixel arrangement. But what’s most interesting about early reports is that the Xperia Z5 Premium does not run seem to run at 4K natively all the time. Some people are confused by this, but I think that it not only makes perfect sense, but that it’s also the most logical solution to making a smooth transition to 4K.

Changing Resolutions

The LG G4 suffered from the resolution jump to 1440p as its Adreno 330 was not quite enough to handle the pixel-pushing required to sustain a smooth 60 frames-per-second. Sony has been vocal about remaining on 1080p to save on battery, yet with the Z5 Premium, they jump all the way to 4K but still claim to offer 2-day battery life. How? Apparently, the device renders at 1080p most of the time, and only uses 4K when it’s needed — be it with a high-resolution pictures or video. This is brilliant, and it’s truly surprising that Sony is the first one to noticeable include dynamic resolutions within their system.

Scaling the resolution up and down is a given on a PC — it’s easily configurable through accessible settings. While no formal settings or toggles allow the same on Android, it can still be done, something which many don’t seem aware of yet it can yield tremendous advantages. Ever since upgrading to my Note 4, I realized that I don’t need 1440p, and in order to improve performance and save a sliver of battery life, I simply lowered the resolution. There are various ways to do it, but the simplest ones are issuing shell commands through ADB (no root) or a terminal emulator. If done with the latter, you must call  su  to request root access.

Then it’s just a matter of firing up the following lines: wm size 1080x1920  and  wm density 480. Note that the resolution in this example is 1080p, but it can be whatever you want it to be, and the density determines the DPI, which logically scales differently with each resolution. For reference, the typical DPI of a 1080p Android phone is 480, which is 640 on 1440p. Some phablets like the Nexus 6 and Note5 come with a default of 560, though, which gives you the same UI as a DPI of 420 on 1080p. Some other numbers can be found in the table below, handily compiled by a redditor.

1440p	560	520	493	480	400	360
1920×1080	420	390	370	360	300	270
1600×900	350	325	308	300	250	225
1280×720	280	260	247	240	200	180
960×540	210	195	185	180	150	135
854×480	187	173	164	160	133	120

Why Would You?

While the actual hardware of the screen won’t change nor behave much differently, the GPU on your device will have to work less to move the pixels around, and, in turn, overall graphics performance increases. This is easily noticeable in games that run at 1440p natively, as when they render at 1080p, the GPU can handle them much better. Various on-screen benchmarks also see big improvements in GPU results, sometimes upwards of 80% for certain well-known tests. This means that, for example, a device with a 4K panel running at 1080p on a Snapdragon 801 won’t have the same problems the G3 did by default, despite bearing the same processor and a higher-resolution panel.

The best part is that, for the most part, these things can be done fluidly and in real time with no need for a reboot as long as the applications can scale appropriately (I am looking at you, Samsung Keyboard…). It also follows that if the GPU has to do less work, you could see a very slight increase in battery life. I personally never saw any significant variation, though.

Smart Sony

I believe that the Snapdragon 810 inside the Xperia Z4 would simply not be able to handle the display running 4K at all times. Even though the chipset is advertised to support it without a hitch, real-world experience proves that it’s just a marketing ploy, and even if the Xperia Z5 has heat pipes and thermal paste, I doubt it’d stay smooth driving such a ludicrous amount of pixels at all times. My OnePlus 2 throttles after just 3 minutes of heavy gaming or benchmarking and at that point, it throws disparate results and scores. This is also with a downclocked CPU, kernel adjustments, and better all-around internal specifications.

Reality seems to show that the 4K display is more of a contextual gimmick, but a properly implemented gimmick at least

If Sony is indeed exploiting a variable resolution, they could get the best of both worlds. The truth of the matter is that 4K is impractical on a phone for various reasons. It’s not like there is plenty of 4K content readily available, and media files of that magnitude cripple low-storage devices (the 32GB default of the Z5 Premium is nothing special in that regard). Streaming such content may take a huge toll on your data plan, and not all wi-fi connections are fast enough for that either. All of that for an ultimately small gain in visual acuity that most people won’t be able to tell is there. It doesn’t sound like a great sale, particularly on a phone with a Snapdragon 810 chipset.

But by going down this route, Sony can deliver the same level of performance as all of their other devices, and still output a (perhaps imperceptible) visual advantage if and when the right content is displayed. But best of all (for them, that is), Sony can claim that it has the first 4K smartphone display, and reap all the media buzz that comes with it. While reality seems to show that the 4K display is more of a contextual gimmick, it’s a properly implemented gimmick at least, because an actual 4K display running at all times on current chipsets and batteries seems mostly pointless and understandably inefficient. Sony found a way around it with simple software tricks and an ability that has always been there on Android, yet most people never knew of it.

Moral of the story is, don’t be too worried about your next device’s performance on its native resolution. If a 1440p or 4K panel makes you doubt your phone will be fast and smooth, just plug it to your computer and fire up ADB. Even if we get to the point where no 1080p Android devices exist, nobody is forcing you to choose between a 1080p phone and the latest flagship.

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