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ASUS Zenfone 2 review

The top end model of the latest smartphone series from ASUS is the first to feature 4 GB of RAM. What else does it have to offer? We find out, in this ASUS Zenfone 2 review!

Published onMay 19, 2015

Asus Zenfone 2

Apart from a few drawbacks that can be fixed with software updates, the ASUS Zenfone 2 brings a lot to the table in terms of build quality, specifications, and features, and could prove to be very disruptive in the smartphone market with its budget-friendly price point.

What we like

- Great build quality
- Bright and vivid screen
- Fast charging technology
- Customizable UI
- Fantastic performance
- MicroSD expansion
- Affordable
- 4 GB of RAM

What we don't like

- Mediocre battery
- Average camera
- Weak speaker

Our scores


Asus Zenfone 2

Apart from a few drawbacks that can be fixed with software updates, the ASUS Zenfone 2 brings a lot to the table in terms of build quality, specifications, and features, and could prove to be very disruptive in the smartphone market with its budget-friendly price point.

During CES 2015 back in January, ASUS introduced the follow up to its affordable Zenfone smartphone series with the Zenfone 2. To start of, it has to be mentioned that there are actually three variants of the device that share the Zenfone 2 name, with the version in this review featuring a 5.5-inch 1080p display and a whopping 4 GB of RAM. What does this device have to offer beyond its impressive spec sheet? We find out, in this in-depth review of the ASUS Zenfone 2!

Note (May 19): With the launch of the ASUS Zenfone 2 in the United States, we’ve decided to republish our comprehensive review. Let us know your thoughts on the device!


ASUS Zenfone 2-9

The ASUS Zenfone is technically a mid-range smartphone, but it certainly doesn’t act or feel like one. Things aren’t particularly different or unique in terms of design, and the inspiration from existing devices is obvious, but that’s not necessarily a bad thing, and the build quality is definitely solid. It’s made of plastic like its predecessors, but the phone doesn’t feel cheap in the hand and is very well put together.

ASUS Zenfone 2-27

The device comes with rounded corners, and the back has a significant curve to it that tapers down towards the edges, making for a very comfortable feel in the hand. The plastic back features a faux metallic coating, which results in not only a great look, but also allows for good grip, while preventing the back from collecting fingerprints. The back cover is also removable, giving you access to the two SIM slots and the microSD card slot. That said, the battery is still sealed and non-removable.

ASUS Zenfone 2-10

ASUS states that the Zenfone 2 is a 5.5-inch smartphone in the body of 5-inch smartphone, but while the device is fairly manageable when it comes to one-handed use, it’s certainly nowhere close to what ASUS claims, and in fact isn’t even the smallest in this size category either. A lot of the girth has to do with the somewhat thick bezels along the sides of the display, and the chin below it that houses the capacitive keys. That said, the Zenfone 2 is still a very sleek looking device overall, even if I do wish it was slightly smaller for an easier handling experience.

ASUS Zenfone 2-2

A noticeable design element is the bare left and right sides, with the Zenfone 2 coming with a different take on the standard button layout. For starters, the power button is up top next to the headphone jack, which is actually quite unfortunate, given the hand gymnastics required to reach it. The power button is also extremely flush with the surface, and isn’t the easiest to press. A double tap to wake and sleep gesture is available though, which luckily means that you won’t find yourself reaching for the power button all that often. Like most of LG’s current smartphone lineup, the volume rocker of the Zenfone 2 has been moved to the back and also come with a slightly ridged texture, making it very easy to reach and find by feel. The microUSB port is at the bottom, with the speaker found at the back.


ASUS Zenfone 2-13

The ASUS Zenfone 2 features a large 5.5-inch IPS LCD display with a 1080p resolution, resulting in a pixel density of 403 ppi. Quad HD may be currently trending, but Full HD is nothing to scoff at and is certainly impressive given the budget-friendly nature of this device.

ASUS Zenfone 2-17

The display experience is great, providing everything you’d expect from a high-end panel. The screen is sharp, vivid, bright enough to easily see in broad daylight, and offers fantastic viewing angles. 5.5-inches is a good size for media consumption, and you’ll have a great time watching videos or playing games on this display. The default settings in terms of color calibration are perfectly fine, but you do have the option to tweak the settings more to your liking, with a reading mode that is gentler on the eyes, a vivid mode that drastically increases the saturation, and finally, a manual mode for more granular controls over the display settings.

Performance & Hardware

ASUS Zenfone 2-28

Under the hood, the ASUS Zenfone 2 packs a 64-bit Intel Atom Z3580 processor, clocked at 2.3 GHz, backed by the PowerVR G6430 GPU, and is also the first smartphone to boast 4 GB of RAM. Keep in mind though that the other versions of the device that come with 2 GB of RAM and feature the 1.8 GHz Intel Atom Z3560 processor, so the performance may vary depending on which variant you choose. When it comes to the performance of the 4 GB version, the device feels every bit as snappy and responsive as a high-end flagship. Animations are smooth, applications open quickly, it handles gaming extremely well, and with this much RAM on-board, multi-tasking is a breeze.

To push the device to its limits, I loaded several games at once and switched back and forth between them, and there were no signs of any stutter or slowdown. Of course, this was done merely for the purposes of testing, and isn’t a use case scenario for most people, but the raw power to handle such a thing is still very impressive. 4 GB of RAM may be overkill for some, but the Zenfone 2 is certainly a fantastic budget-friendly option for the power user. The only hiccup was with regards to the Instagram application that simply crashed all the time. This could be due to compatibility issues with the Intel processor, and is hopefully something that will be fixed with a future update. It could be a huge drawback for heavy Instagram users, and is a small blemish to what is an otherwise solid performance.

ASUS Zenfone 2-5

The device packs a standard suite of connectivity options, including support for 4G LTE which does work in the US, and I had no issues with getting high-speed internet on the T-Mobile network. 16 GB, 32 GB, and 64 GB of on-board storage is available, with further expansion via microSD possible up to 64 GB. The rear speaker is denoted by a very large speaker grill that gives the illusion of the phone packing a powerful speaker. That is unfortunately not the case though, with it having just a small single driver placed on the left side of the grill. The sound quality is adequate, butit doesn’t get very loud when compared to some other devices with similar speaker setups.

ASUS Zenfone 2-11

The Zenfone 2 comes with a non-removable 3,000 mAh battery, that, coupled with the power frugal Intel Atom chip, should allow for some great battery life, but that unfortunately has not been the case. As you can see from the screenshots below, while it is possible to get a full day of use out of the device with around 4 hours of screen-on time, there are significant battery drain issues from the Android OS that is drastically shortening the battery life. It’s difficult to pinpoint whether the cause is in the initial version of Android 5.0 Lollipop, which has been known to be buggy, with a lot of issues being resolved with the jump to Android 5.0.2 and now Android 5.1, or whether the problem is with the Zen UI itself.

Thankfully, ASUS is aware of this issue and is working hard to fix the problem. That means a future update should eventually solve the battery woes, and we’ll be sure to report on this as soon as it hits. On the bright side, the Zenfone 2 does come with fast-charging technology, which ASUS claims will restore 60% of battery life in a little more than half an hour.


ASUS Zenfone 2-4

The ASUS Zenfone 2 comes with a 13 MP rear shooter, with a dual tone LED flash, and a respectable aperture of f/2.0. Like previous generations, this device also features ASUS’ Pixelmaster technology that is supposed to provide better shots and video in low light conditions. The camera application is fairly straightforward and easy to use, and includes all the usual setting that you would expect, such as white balance, exposure, ISO, and 1080p video capture, and some typical shooting modes are also available, including manual, HDR, and panorama.

ASUS Zenfone 2-21

Like a lot of smartphone cameras, the camera of the Zenfone 2 performs best in good lighting conditions, with the f/2.0 aperture allowing for some nice depth of field. That said, the biggest issue with this camera is the lack of dynamic range. While it is capable taking a decent shot, more often than not highlights were either completely blown out and overexposed, or right at the other end of the spectrum with images being too dark and underexposed. HDR mode proves to be the savior here, and works quite well to even out the images, while adding some extra saturation as well. HDR image processing does take a long time between shots though, so if you don’t have a steady hand, or the subject is moving, the image will be not be particularly sharp.

ASUS Zenfone 2-22

Image quality deteriorates as lighting conditions worsen, with photos starting to exhibit noise, and the image quality becomes worse when shot at ISO 300 or higher. ISO is capped at 800, which limits the amount of noise that could potentially be introduced, but even then, the camera’s image processing doesn’t handle the existing noise all that well. The built-in low light mode takes advantage of the Pixelmaster software to allow for up to 400% brighter photos, and while it does work, the images are of a lower resolution, and the increase in light actually makes the digital noise even more visible.

If you enjoy taking self-portraits, the front-facing 5 MP camera with a wide angle lens will certainly get the job done. The camera comes with a real-time beautification feature, and there is also a selfie panorama mode that will help you easily fit your friends or family into the shot.


ASUS Zenfone 2-20

The ASUS Zenfone 2 comes with Lollipop out of the box, but as mentioned, it is Android 5.0, and not the newer Android 5.0.2 or the latest Android 5.1. On top is the ASUS Zen UI, but it does retain some of the material design elements of Lollipop, noticeable in the notification shade and the Recent Apps screen. That said, those familiar with the Zen UI will still feel right at home here.

ASUS Zenfone 2-26

There are a lot of bloatware applications on-board, but a handful of features do add to the overall experience, like an Easy Mode that creates a simplified interface, and a one-handed mode, which, as the name suggests, allows for comfortable one-handed use, and can be triggered by a double tap of the home button. There are also a few gestures that can be used while the screen is off, that ASUS calls ZenMotion, which includes the double tap to wake feature and also allows you to draw different characters to launch specific applications. The Zenfone 2 also eliminates the need for carrying two separate work and personal devices, with the build-in Snapview feature allowing users to create completely separate and secure profiles to store business or personal data that only you can access.

One of the main attractions of the Zen UI is the ability to customize the interface with the built-in theme engine, that can be used to alter the look and feel of the entire experience with different fonts and icons, as well as changes to the lock screen and notification shade. The launcher preferences can also be customized simply by swiping up from the bottom, or by a long press on the home screen. While standard settings like widgets, wallpapers, and various home screen scroll effects are available, the best part about this launcher is the ability to use third party icon packs from the Google Play Store, something that is otherwise only possible with a third party launcher.


Display5.5-inch IPS display with 1920 x 1080 (Full HD) resolution. Corning® Gorilla® Glass 3.
64-bit Quad Core Intel® Atom™ Z3560/Z3580 processor (running at 1.8 or 2.3GHz).
PowerVR G6430 from Imagination
2GB or 4GB.
16GB/32GB/64GB, microSD card slot, up to 64GB.
Rear: 13MP, f/2.0-aperture, 5-element, auto-focus lens with dual-color Real Tone flash. Front: 5MP, f/2.0-aperture, wide-angle 85-degree lens with Selfie Panorama.
3000mAh lithium-polymer with fast-charge technology.
802.11ac, Wi-Fi Direct, Bluetooth 4.0, NFC, GPS
Android 5.0 Lollipop
152.5 x 77.2 x 10.9-3.9mm, 170g


Final thoughts

The ASUS Zenfone 2 is available now in select regions like China, Taiwan, and Europe, and will soon be releasing in India in the coming weeks, but US availability is still to be announced. Available colors include black, gold, gray, red, and white, with pricing starting at $199 for the base model. Official pricing for the higher-end models will be announced by ASUS later this month, but you can expect it to range anywhere between $50 to $100 above the base price, depending on the RAM and the storage option.

ASUS Zenfone 2-12

So there you have it – a closer look at the ASUS Zenfone 2! Once the battery life issues are resolved, this device is going to be a major contender in the Android smartphone world. Boasting a beautiful design, powerful specifications, and a solid user experience overall that will cater to a variety of users, it’s hard to imagine that all of this is available at such a budget-friendly price point. ASUS is proving once again that you don’t have to pay a lot to get a lot, and the Zenfone 2 is certainly setting a new standard for the affordable smartphone market.

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