ASUS ZenFone 2 review (4GB RAM, ZE551ML) – ASUS is definitely up to something here

ASUS is mostly famous for its notebooks and desktop components, but recent changes in the market pushed the company to enter the mobile segment. The ever growing mobile industry attracts a lot of vendors. Furthermore, expensive and high-end smartphones seem to be selling in smaller quantities with the years passing by while the mid-range and low-end handsets start to make a significant dent in the market share. Most importantly, cheaper smartphones begin to look, feel and perform more like high-end devices and here is where ASUS steps in.

Their latest flagship ASUS ZenFone 2 is offered in two variants – with powerful Intel Atom Z3580 and Z3560 and the first one being more powerful and equipped with 4GB of RAM, while the second one appears to be a more budget variant with 2GB of RAM. The best part is that either choice doesn’t exclude the features that make this smartphone so great. Nonetheless, subject of our review is the more powerful version of the handset and its ridiculously cheap – around €400. Specs just like every other flagship out there at a reasonable price – so cheap that it falls into the upper-mid-range category. Although, we need to make fair assessments of the qualities of ZenFone 2.

Contents

Retail package

The box containing the phone carries inside the usual accessories like AC charger, USB cable for charging and file transfer, and earbuds. You will also find user manuals and instructions for use.

Design and construction

If you are wondering how ASUS has kept the costs low for its flagship device, look no further than the design and materials used. However, don’t get us wrong – the plastic used here isn’t bad or cheap by any means. It feels good, sturdy and yet stylish which proved to be the sweet spot for ASUS. They’ve managed to design a phone that looks great, feels great and at the same time keeping the costs low.

Starting with the back of the phone which can be easily mistaken for brushed aluminum and it looks almost identical to the one we saw in the LG G3 last year. Actually, we are going to draw a lot of similarities to the LG G3 during this review as both phones really look alike. The bottom part accommodates the loudspeaker grill and right above it the Intel and ASUS ZenFone logo. Moving up to the upper part where the 13MP sensor and dual-tone LED flash are placed along with the volume rocker. Yes, you’ve guessed it – the volume keys are placed on the back just like the LG G series smartphones, but without the power button to accompany them. You will easily adopt them thanks to the little protruding volume up key so you will know whether you are going to turn up or down the sound. Note that the back cover is easily removed by the user, but it pops a little bit harder to our taste. Under the hood, you will find the micro SD card slot, the two SIM card departments, and the battery which, unfortunately, can’t be removed without disassembling the device. It would be quite interesting to know what are the design limitations for not making the battery user replaceable.

Going around the front, you will see the huge 5.5-inch display with Gorilla Glass 3 protection, front-facing camera, the earpiece and the physical touch capacitive buttons at the bottom. Under them is the iconic concentric-circle pitch. ASUS claims that the screen-to-body ratio is 70.1% which might sound good, but in practice the ratio doesn’t deliver what we’ve expected. The bezels around the screen are somehow thicker than they should be and due to the fact that the phone is quite tall it’s hard to reach the top edge of the screen. On the other hand, this is normal for a 5.5-incher as people with normal and small hands will have trouble navigating with one palm. Still, thinner bezels wouldn’t hurt and the presented design makes the device bigger than it already is.

The sides, however, are thin (3.9 mm) and you won’t find anything special around its profile. Just the usual micro USB port and main microphone at the bottom and the power button, 3.mm jack for headphones plus noise cancelation mic at the top. To be honest, ASUS should have gone full G series here with the power button placement. You will barely use the power button as the smartphone supports various gestures to wake up the screen as the current placement is impractical – makes it hard to reach with one hand. As for the gestures, you can read all about it in the “Software” section of the review.

Our overall opinion of the build quality is good. Despite the polycarbonate design, the device feels stylish and it’s really good-looking. The arc design on the back makes up a bit for the size of the phone and you can hold it more comfortably. Unfortunately, though, the brushed aluminum-like back is a bit slippery and the thick bezels will make you worry about dropping it more than it should. Also, no irregularities, dents, holes and etc. were found.

Display

The panel used for the making of the ASUS ZenFone 2 (ZE551ML) is Full HD IPS with Gorilla Glass 3 protection. The diagonal is 5.5 inches, aspect ratio 16:9 and a resolution of 1920 x 1080 pixels. These numbers lead to pixel pitch of 0.063 x 0.063 mm or simply put – 403 ppi (pixels per inch) pixel density. The screen is considered “Retina” when viewed from at least 23 cm.

Viewing angles are good, without any major distortion of the image quality when viewed from 45-degree angle.

ZenFone 2’s software offers several screen presets with each one giving you different viewing experience. They are “Balance”, “Vivid”, “Reading” and “Customized”. Also, the color temperature can be further adjusted. So we tested the maximum brightness and contrast in “Balance” mode and native color temperature. The results are 335 cd/m2 and 910:1 contrast ratio.

Color reproduction

ZenFone 2’s display covers 94% of the sRGB and 71% of the Adobe RGB color gamut.

Color reproduction

The colors appear to be fairly accurate with average deviation of DeltaE 2000 listed below.

Pulse-width modulation (PWM, Screen flickering)

We did not found any aggressive light pulsation, no matter the brightness level. The display is harmless to your eyes.

Gaming capabilities (Response time)

The graphics below illustrated the time which takes for the pixels to light up from black to white and white to black with levels set from 10% to 90% and vice versa. Fall time + Rise time = 16ms.

Conclusion

All tests confirm that the panel of the device is of a good quality without any major issues. It has good pixel density, it covers 94% of the sRGB color gamut and it doesn’t have the so-called screen flickering. However, the color reproduction seems a little of, but we doubt that the general user will notice this. And another thing – the maximum brightness (345 cd/m2) is insufficient when working with the phone outdoors. The image is barely visible under direct sunlight.

Display comparison

Battery life

Well, looking at the specs sheet we would normally expect at least a full day of normal usage or maybe two depending on your routine. The smartphone is powered by 3000 mAh battery that has the hard task to juice up the powerful SoC and the 5.5-inch 1080p display. We ran the usual tests – Wi-Fi web browsing, video playback, 3G web browsing, talk time and gaming. All tests exclude GPS, Bluetooth, and screen brightness is set to 120 cd/m2.

Moreover, the SoC supports fast charging thanks to the BoostMaster charger which is included in the package, but only users with the 4GB version can take advantage of the fast charging feature. Speaking of which, the BoostMaster charger can juice up your smartphone for 60% of the battery capacity for about 39 minutes. More on the battery saving features – in the “Software” section below.

Specs sheet

Operating system	Android 5.0 (Lollipop)
CPU	Intel Atom Z3580 (4-core, 2.30GHz, 2MB cache)
RAM	4GB RAM
Storage	64GB flash memory + microSD card up to 64GB
GPU	PowerVR G6430
Display	5.5-inch IPS, Corning Gorilla Glass 3 protection, 1080 x 1920 resolution
Connectivity	Bluetooth v4.0, A2DP, EDR, Wi-Fi 802.11 a/b/g/n/ac, GPS, A-GPS
Cameras	13MP with autofocus, dual-LED flash + 5MP front-facing
Features	Micro-SIM, dual stand-by, dual call microUSB v2.0 (MHL TV-out), USB Host accelerometer, gyro, e-compass
Battery	3000 mAh
Dimensions (W/H/D)	77.2 x 152.5 x 10.9 mm
Weight	170 g (6.0 oz)

Software and Zen UI

Take a look at this official ZenUI clip, made by ASUS, showing the most interesting features in its user interface.

First Start and pre-installed applications

When you power up your phone for first time you’ll have the chance to choose your language, input keyboards, Wi-Fi hot spot, configure Google and ASUS accounts (you’ll get 5GB of free cloud storage if you create an ASUS account), transfer contacts, calendars, messages and bookmarks from your old device and decide if you want to share anonymous usage data in order to “Inspire ASUS” (and help them improve their services).

ZenFone 2 ships with lots of the so-called “Bloatware” – after the first boot, you’ll be swamped with exactly 65 pre-installed apps. Chances are you won’t need most of them and unfortunately you can’t get rid of them completely but at least they can be “disabled” so they won’t show up in your menu (they’re still going to use some of your storage, though).

Update: The latest update allows uninstalling some apps.

After updating to the latest firmware (LRX21V.WWASUS_Z00A-2.15.40.13_20150506_3876_user), you’ll end up with 9.76GB of free storage for your needs. As we added above, the latest update lets you uninstall some of the pre-installed apps. After deleting TripAdvisor, Clean Master and some more “partner software” we managed to get 9.83GB of free space.

Along with the garbage, you can find not a few useful apps, too. For example, Do it Later is sophisticated “To Do” application which can be synced with Google Tasks. File manager works with 3rd party services like Dropbox, Google Drive and OneDrive, as well as with ASUS’s own WebStorage and HomeCloud.

Kids Mode is an intelligent app for easy parenting. ASUS knows that you won’t be able to hide your phone from the tiny hackers in your house, so at least you can restrict the apps they can use, the time they can play and the sites they visit. Kids Mode automatically scans if any particular site is for adults and don’t load it (it works only with the Browser app).

Everything is protected by four-digit PIN code, so if you don’t set a 0000 or 1234 one, they’ll have some hard time guessing it (this doesn’t mean they won’t success).

PC Link gives you the opportunity to use your computer to control Zenfone – you can write longer messages faster on your physical keyboard and you can work with your smartphone on the bigger monitor.

Share Link and Party Link let you share your multimedia on other devices. The latter give you the option to create user groups.

Remote Link is a remote control for your PC, which is convenient when you’re making presentations.

The Power Saver app lets you choose between three smart saving modes – Normal (turned off), Optimized mode (optimizes the performance) and Ultra-saving mode (reducing performance and background data).

ASUS ZenCircle is something like a social network – you can capture, edit and share special moments and events. Then you can share them in the most popular social networks, if you want, or you can follow another ZenCircle users.

What’s next is organizer app which keeps you in touch with everything that happen around you. Weather, events, meetings, etc.

PhotoCollage can automatically mix your photos in a collage. You can add stickers and text and you can choose from several different puzzle types.

You can save the result in resolutions up to 2560 x 2560 pixels (for a 1:1 ratio).

MiniMovie is a small app, which can build videos, based on your camera captured multimedia. You have several styles to choose from, and the result is short .mp4 video, an example of which you can see below.

Of course you won’t be left without the ordinary apps like the Google Services, Calculator, FlashLight, QuickMemo, Sound Recorder, Music and even FM Radio.

Settings

Easy Mode, ZenMotion, ASUS customized settings

The most interesting thing here – ZenMotion. You have 6 different gestures for 6 applications which can be started directly from sleep mode. For example, if you draw W on your screen while it’s turned off, you’ll start Browser. C is for Camera and V is for Phone.

Performance

ASUS ZenFone is powered by quad-core Intel Atom Z3580 SoC with a maximum frequency of 2.33GHz and 2MB LL cache. The CPU also supports 64-bit set of instructions and its lithography is 22nm. It’s equipped with the whooping 4GB of dual-channel LPDDR3 1600 memory which is pure overkill by any means. The GPU is PowerVR G6430 and ticks at 457MHz and can go up to 533MHz. The entire SoC is able to deliver more than a good performance from user’s standpoint. We didn’t notice any lags or hangs and everything ran perfectly smooth. Don’t be disappointed by the date of release of the CPU (Q2’14), though. It looks like this is another cost that ASUS was able to cut off the price of the phone and we don’t blame them. The ZenFone 2 will run everything you throw at it with no problem. However, we did a set of benchmark tests to assess and determine a relative performance that can be compared to other models from the same price range on the market.

CPU

GPU

Camera

The device is equipped with 13MP (4129×3096) sensor manufactured by Toshiba, 1.12 μm pixel size and aperture of f/2.0.

Resolution

We measure the resolution of the image, which is the final product of the sensor and the matrix, with the provided ISO 12233 table in lph (lines per high).

The maximum resolution at the center of the table is quite high. Good result.

Using our test composition, we can gain a subjective but fairly accurate view of the resolution, sharpness, color noise and chromatic aberrations.

As you can see from the image below, the text is hard to read and there are a lot of traces from the JPEG compression.

Chromatic aberration and noise

No traces of chromatic aberration.

There’s little noise and the dark parts of the image are well managed.

Color reproduction

Our rating is 7.0/10

You can see the difference between the input and output colors on the color map below.

Conclusion

ASUS ZenFone 2’s camera is able to capture detailed images with good colors, but they are a bit oversaturated in red. There’s also a room for improvement when it comes to JPEG compression and noise in low-light conditions.

Sample photos

Sample photos in brightly lit conditions

Macro photos

Sample photos in reduced light conditions

Video recording

To see the video in its actual quality, click on the gear (lower right) and choose the highest resolution.

Temperatures and comfort

That’s an important aspect of every smartphone that’s easily overlooked. With the advancement of the SoCs these days and the more demanding games and apps can produce a lot of heat under the hood, we did our best to assess how the smartphone handles bigger loads and higher temperatures. Most importantly, how all of this affects user experience.

For our test in this section, we used Epic Citadel again running on loop. After more than 30 minutes of non-stop gaming we measured three even parts of the surface on the back (where you usually hold the phone). You can see the results on the heat map above.

Verdict

Even though ASUS isn’t renown with its mobile devices, we are sure that the Taiwanese company is on the right track. ASUS’ flagship smartphone might be missing some key features that are present in today’s top-tier handsets like the LG G4, Samsung Galaxy S6 and etc. However, the hardware, design, the Zen UI, and performance can easily match each and every one of the competitors out there. Practically, you get a smartphone with great battery life, appealing design, good screen quality for a price that matches a typical upper-mid-ranger.

Nonetheless, specs sheet doesn’t determine the smartphone as a whole and there are some flaws which cannot remain neglected. For starters, the display isn’t bright enough to ensure comfortable use outdoors, color reproduction is a little off. Also, despite the excellent build quality, the surface is quite slippery and the bezels around the screen are way too big for a normal one-handed usage. Luckily, the Zen UI offers a few tricks to ease the usability in this aspect. The camera performance is good enough for day to day usage, but the JPEG compression and the noise are easily noticed on some of the photos. And finally the SoC. It’s powerful, it will manage everything you throw at it, but there’s something that’s bugging us and it’s the date of release. The Intel SoC has been released a year ago and it’s hard to compare it to todays flagships as they feature newer SoC technology. The good part is that the smartphone comes at an amazingly low price and the general user won’t feel the difference between last year’s hardware and this year’s technology.