ASUS Zenfone 2 Review (4 GB RAM ZE 551ML ) : A beast with moderate battery and Camera

Asus Zenfone entered the smartphone market last year with Zenfone 5 and were able t disrupt the market by creating a niche for the device. The latest offering from them is the Zenfone 2 with 4 GB RAM. Finally we got our hands on ASUS Zenfone 2 for review.

This post is based on our experience with ASUS Zenfone 2 that we had while testing it for more than two weeks as our primary smartphone. The variant that we tested is the 4GB RAM variant with 1080p screen resolution. Here is our full review of the Asus Zenfone 2.

ASUS Zenfone 2

Brief Specifications

  • Display : 5.5 inch Full HD IPS
  • OS : Android 5.0 Lollipop
  • CPU : 2.3 GHz Intel Atom Z3580 Quad Core Processor
  • Camera  : 13 MP Primary with dual-LED real tone flash  + 5 MP Secondary
  • Dual Sim (GSM + LTE)
  • 32 GB ROM + Micro SD Card support upto 64 GB
  • 4G (LTE) – 150 Mbps HSDPA, 50 Mbps HSUPA
  • OTG Support

Design and Build Quality

Zenfone 2 comes with plastic removable curved rounded plastic back and faux brushed aluminium texture with a metallic finish giving it a premium look. ASUS relocated the Volume rocker to the back cover and the Power button to the top just near the audio jack. This design change makes it almost similar to LG’s G4 in terms of those two buttons. The curved design at the back makes the sides appear quite thin.

Honestly I am not sure what prompted this move. Even after using it for almost more than two weeks, we were not comfortable at all with these buttons as the size of the device makes it difficult to reach the buttons easily with one hand. It may be a bad design move for users like me. But as I keep saying, its my opinion and may be other users may like this. ASUS though tried to cover this drawback by providing a double tap feature to wake up the screen.

The menu  buttons at the bottom of the screen are not backlit which makes it a bit uncomfortable to use it in dark surroundings. The speakers are at the back of the device at the bottom with a grill across the width, even though if you open the back cover, speaker is just at one side.

The battery at the back is non removable even though you can open the back cover.


It comes with 5.5-inch Full HD IPS Display with Gorilla Glass 3 protection and resolution of 1920 x 1080 pixels. The display appears great if you have manually set the brightness. It appears a bit dull if you set it to auto adjust mode. The display was good enough and adjusted itself quite well even in surroundings outside with heavy sunlight. We were able to use it without any issues in heavy sunlight. It also comes with great viewing angles letting you view the screen even at steep angles.

It also comes with display tuning app letting you choose different screen modes like Standard, Reading, Vivid or Balanced or you can customise one for yourself. It also comes with Glove mode if you want to use it with your gloves on in winter.

Performance and Benchmarks

When it comes to performance, you can call Zen 2 as a beast. We played some heavy games like Asphalt 8 on it simultaneously with other games and using other features of the phone, yet we never felt any issue in terms of performance. Whatever we threw at it, it ran / executed that excellently without any lag or performance issues. The graphics details in the games and HD videos was great. If you want a smartphone for multitasking, this device is for you. If you are an avid game lover on smartphones, you should grab this device for sure.

We never faced any issue like heating of the device while playing intensive games, multitasking or using the device for too long or in any other scenario.

Zenfone 2 Antutu Benchmark score

The benchmarks scores for zenfone 2 beats almost every other device in the same price range and even competes with more expensive devices. Antutu benchmark score came out to 46,000+ almost competing with Note 4.


Similarly, we got great scores in Velahmo benchmark tests.


It comes with 13 MP main rear camera with dual-LED real tone flash and a front 5 MP front camera. We took the camera to test with different lighting conditions. If you are a average smartphone user and use the default auto settings for taking pictures, then don’t keep too much expectations. The pictures taken were good if we took those pictures in bright and sunny conditions. But the quality wasn’t good if we had even marginal dark surroundings which include the evening conditions and pictures taken inside home or buildings with no direct sunlight.

But if you are a professional photographer, you are in for a treat. The Zenfone 2 comes with a manual mode just like DSLR’s which lets you adjust settings for ISO, shutter speed, white balance, exposure compensation and selective focus. If you good in setting these, the pictures taken from the device turn out to be great. The manual mode also shows you the histogram when you are clicking the pictures letting you shoot great pictures.

The camera comes with loads of modes such as Low Light mode, Selfie mode, night mode, super resolution mode, HDR mode, Panorma mode and much more. Out of these, we like the selfie mode which lets you take selfies using the main 13 MP camera by detecting the faces and clicking itself automatically to shoot the selfie.

The front 5 MP camera though performed great and produced some good pictures. We were more than surprised by the quality of the front camera compared to even the main camera sometimes.

Camera samples

Checkout the images below taken under different light conditions and different modes. Click on the images to enlarge to original full size image.


Even though the Zenfone 2 comes with a 3000 mAh Li polymer battery, it fared just like any other good smartphone. On an average, the battery on the device lasted for full day with average usage with 3G on and doing usual tasks like receiving / making some calls, checking gmail, twitter, Facebook etc., playing a bit of games. But on a heavy usage day, the device needed to be charged before evening. The device standby time is not good and if before sleep if you got a battery of ~15% then it is possible that when you wake up in the morning, the device will be dead already.

We were unable to test battery performance on 4G network as it’s not yet available in New Delhi.

Operating System and UI

Zen 2 is powered by Android 5.0 Lollipop operating sytem with ASUS own user interface ZenUI on top of it. We are not a big fan of custom UIs from OEMs running on top of stock Android, yet we do like the ZenUI. ZenUI for us appears to have precise integration with the stock Android UI and it doesn’t feel like a different or new user interface. Also, it is clean and simple compared to other OEMs. You can treat this as my opinion and many of you may differ with me on the ZenUI.

It comes with some custom features from ASUS such as the ultra saving mode, optimised mode or customised mode for battery. Apart from this, it also comes with support for gestures using which you can open applications without even unlocking the device. You can customise the gestures as per your need quite easily.

You can customise the toggles in the notification area as per your needs.

One of the things which may face some ire from users like me, is about the pre-installed bloat-ware. There are many apps which come pre-installed on the device and users who like to have a stock android experience may not like it. I prefer a smartphone should come with basic minimum apps pre-installed. Users obvious;y can install the apps they need.

It also comes with a 100 GB Google driver offer which you can redeem while setting up the phone initially.

Zenfone 2 Google drive 100 GB

Youtube Video Reviewing Zenfone 2


In conclusion, we can say for sure that this device is a beast when it comes to performance.  It comes with awesome performance for gaming, multitasking and whatever not with 4 GB RAM, a stunning display, great Camera under Manual Mode for Professional Photographers and support for Quick Charging. The only department where it lags a bit is the camera under default auto conditions.

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Avinash Kumar
Founder- Editor at Androidpure : A Mechanical Design Engineer by profession, but passionate about Computers, Smartphones, Gadgets, software and anything that helps to learn something new or different. Love to do things which i don't know and dive into unknown territories.

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