This is the third article in a series of posts in which we talk in detail about the ASUS Zenfone 5Z – the newest flagship grade smartphone from ASUS. In the previous articles, you read about the design and software aspects of this phone. In the last article, I also talked about the display quality of the device. In today’s article, we delve deeper into the performance aspects of the device and check how this smartphone fares against its rivals. As you might be already aware, competition is pretty intense in this price segment, and currently, ASUS stakes claim for offering the most affordable flagship class handset you can buy today.

ASUS Zenfone 5Z: Hardware and Performance

The Zenfone 5Z is famously powered by the Qualcomm Snapdragon 845 SoC that is currently the fastest processor available for Android smartphones. Our review unit was the base 6GB RAM + 64GB version. There are two other versions – a 6GB RAM +128GB variant and a top of the line 8GB RAM +256GB version. Unlike its chief competitor the OnePlus 6, the Zenfone 5Z gives the user the option to expand the phone’s storage capacity further using a microSD card slot. In case you do not wish to use a memory card, you can use the slot to insert a second SIM card.

Diving Deeper

After initially setting up the device, I found that the performance on the software side of things were a bit laggy. This was outlined in my previous article where I talked about the software aspects of the Zenfone 5Z. However, things were quickly back on track after I updated the handset to the final retail software just a few days before the launch. The handset now feels as fast as the OnePlus 6 during my time with the handset. In fact, the Zenfone 5Z consistently manages to beat the OnePlus 6 as far as the initial boot time is concerned. The only chink in the Zenfone 5Z’s armour is perhaps the ZenUI interface which might initially not appeal to someone coming from a stock Android background. However, you should be able to get used to it under a weeks time.

I did not use the handset long enough to check how good ASUS’ Optiflex technology works – but post the aforementioned software update, the Zenfone is as fast as the OnPlus 6 in every aspect. In fact, there were several occasions when many apps opened faster on the Zenfone 5Z than on the Oneplus 6. In case you prefer looking at benchmark scores, and not just real world scores, the Zenfone 5Z found itself neck to neck with the OnePlus 6. Note that the OnePlus 6 unit that I had had 8GB of RAM which sort of tilts the results ever so slightly in its favour.  In case you were wondering what ASUS’ OptiFlex technology is, this is an AI feature that learns your app usage habits and keeps your most frequently used apps in the memory,  eventually resulting in these apps opening faster for you. In the AnTuTu Benchmark test, our review unit managed a score of 270188 points which is right up there among the best in business.

Even though not an avid gamer, I was able to experience a lag and stutter-free gaming experience on the Zenfone 5Z. The phone also did not show any signs of excessive heating even during intense gameplay. The phone also gets the AI boost option that automatically allocates additional RAM to a resource intensive app for better performance.

Battery Life: On par with the competition

The ASUS Zenfone 5Z gets a 3300 mAh battery. My previous experience with ZenUI made me believe that I should not expect more than 5 hours of screen on time on the 5Z. True to my expectations, when I used the handset with the brightness turned to max, the phone actually ended up with a screen on time of less than 4 hours. However, I do realise that this is not how most users would use the phone. I then tested the handset with the brightness setting set to auto and was able to easily eke out over 6 hours of screen on time. To sum things up, the Zenfone 5Z will easily last you a day even with heavy usage occasionally. The battery also supports QuickCharge 3.0, and I managed to charge the battery from 0 to 100% in around 1 hour 37 minutes which is impressive again. I wasn’t able to judge call quality on the phone because both the networks that I am on currently – Jio and Airtel – are absolutely horrible in Hyderabad. The earpiece, however, was loud enough and you should be able to hear the person at the other end without issues. Another useful feature that I found myself using all the time was the AI charging functionality. With this feature enabled, the phone tracks your charging habits and adjusts the charging speed. For example, if you have this habit of charging your phone overnight, there is actually no need for the handset to use QuickCharge. In such a scenario, the phone charges slowly, thereby increasing the overall lifespan of your battery.

You can also use the Mobile Manager App that the phone ships with to customise almost all possible battery centric features. This software allows you to stop battery consuming apps that run in the background and prevent random apps from auto-starting. The app also has a Power-safe technology option that claims to protect the handset from a variety of electrical issues.

In the next article, we will take a detailed look at the camera app and the imaging capabilities of the Zenfone 5Z. Watch out for that one!