[nextpage title=”Introduction”]
The ZenFone 2 is the new smartphone from ASUS, with a Full HD (1920 x 1080) 5.5” screen, 4 GiB of RAM, 32 GiB of storage,13 Mp rear and 5 Mp front cameras, Intel Atom Z3580 quad-core 2,3 GHz CPU, support to 4G LTE and Android 5.0 “Lollipop” operating system. Let’s see if is it a good smartphone.
The ZenFone 2 is the second generation of the ZenFone 5 and the ZenFone 6, both of which we have already reviewed. In the first generation, the number specified the screen size in inches, but on the new model the number designates its generation.
The model we tested is the ZE551ML, with 4 GiB of RAM, Atom Z3580 (2,3 GHz) CPU, and 32 GiB of storage memory. There are also other models, with option for 2 GiB of RAM, Atom Z3560 (1,8 GHz) CPU, and storage from 16 GiB to 64 GiB.
Figure 1 shows the box of the ASUS ZenFone 2.

Figure 1: box

Inside the box, besides the smartphone, there is a wall charger, USB cable, and the user manual.

Figure 2: accessories

Figure 3 reveals the ASUS ZenFone 2 (at the right), at the side of the ZenFone 5 (left). The design is pretty much the same, with the three Android buttons present as capacitive ones under the screen, and the front camera at the upper right. The area under the buttons is made of brushed aluminum (now in black), which gives the smartphone a classy touch.
Besides the bigger screen, the ZenFone 2 is only a little bigger than the ZenFone 5.

Figure 3: the ASUS ZenFone 5 (left) and the ZenFone 2 (right)

[nextpage title=”Overall Look”]
The ASUS ZenFone 2 uses an Intel Atom Z3580, which has four cores running at 2.3 GHz. The GPU is a PowerVR G6430.
It has 4 GiB of RAM and 32 GiB of storage, but it can be found with 2 GiB of RAM and 16 GiB or 64 GiB, as we mentioned before.
The 5.5-inch IPS LCD screen has a resolution of 1920 x 1080 pixels (Full HD), which excellent image quality and viewing angle. Until now, we have seen Full HD screens only at high-end smartphones.
Figure 4 shows the back side of the device. The back cover is removable, made of plastic with a finishing that looks like brushed aluminum. Our sample came with a silver cover, but there are also black, white, red, and gold models.
There are openings on the cover for the camera, the dual tone flash, and the speaker (at the bottom). The volume buttons are in the rear too, under the camera. It allows the device to have thin edges, with only 0.15” (3.9 mm).

Figure 4: back side

Figure 5 shows the top of the ZenFone 2, where it has the secondary microphone, the power button, and the earphone jack.

Figure 5: top side

At the bottom are the main microphone and the MicroUSB/charge connector.

Figure 6: bottom

There are no buttons or connectors at the sides of the smartphone.

Figure 7: right side

Figure 8: left side

In Figure 9 you can see the back cover removed, showing the microSD slot and the slots for two micro-SIM chips. The ZenFone 2 supports microSD cards up to 128 GiB. The battery is not removable. Glued to the cover, you can see the NFC antenna.

Figure 9: back cover removed

[nextpage title=”Using the ZenFone 2″]
As expected for a smartphone with such high specifications, the ASUS ZenFone 2 is excellent to use. The Atom Z3580 quad-core processor running at 2,3 GHz, along with the 4 GiB of RAM, make the smartphone very agile, with no signs of slowness.
The 5,5” screen is excellent and the resolution of 1920 x 1080, with 403 DPI, is worthy of a high-end device. Just for comparison, it is said that the human eye can see details at the maximum of 300 DPI.
The ZenFone 2 supports two SIM chips, with 4G LTE support only on the first chip.
The device also supports NFC, which is a short distance communication standard for data transfer and electronic payments.
The phone is pretty big, measuring 6” x 3.04” (152,5 x 77,2 mm), and it weighs 6 oz. (170 g.) It is not thin, because of its 0.43” (10.9 mm) at the center. But thanks to the curved design with thin edges (0.15” or 3.9 mm), it is comfortable to hold.
The ZenFone 2 comes with Android 5.0 operating system. The interface is the ZenUI, the same used in the ZenFone 5, very intuitive and easy to use.
Figure 10 shows the initial screen when you turn on the ZenFone 2 for the first time.

Figure 10: main screen

Pressing the icon with six dots, you enter the list of applications, shown in Figures 11, 12, 13, and 14. The ZenFone 2 comes with a lot of preinstalled apps and games.

Figure 11: list of applications

Figure 12: list of applications

Figure 13: list of applications

Figure 14: list of applications

You can install new applications using the Google Play Store, which has thousands of applications and games available.
The smartphone uses a 3,000 mAh lithium battery, with a good endurance for this kind of smartphone. We ran the battery benchmark of the Android PCMark app, and it measured 5 hours and 33 minutes, which is a good time.
The ZenFone 2 comes with the “BoostMaster” charger, which allows to charge 60% of the battery in 39 minutes, or talk for 4 hours with only 10 minutes of charging, according to ASUS.
The 13 Mpixel camera is excellent. It is also able to record Full HD movies, but only with 30 fps. The smartphone does not support 4K recording.
The front camera (for video chat and “selfies”) has a 5 Mpixel resolution, which is also compatible with high-end smartphones.
[nextpage title=”Performance Tests”]
In order to check the performance of the ASUS ZenFone 2, we ran some benchmarking apps. We ran the PCMark Work test, which simulates real world tasks, the 3DMark Ice Storm Unlimited benchmark, which measures 3D performance, and AnTuTu 5.7.1, which runs several performance tests, including memory, storage, and 3D graphics benchmarking to create a final score. We also ran the same tests on the ZenFone 5 and on the Samsung Galaxy S6 Edge.
Keep in mind, however, that the smartphones tested are not direct competitors, because they have very different price points. The ZenFone 5 stays in market at a lower price range, while the Galaxy S6 Edge is one of the most expensive smartphones available. We just include them to compare the performance of the ZenFone 2 to a high-end device, as well as to the first generation ZenFone.

In the PCMark Work benchmark, the ZenFone 2 was 50% faster than the ZenFone 5, and 14% faster than the Galaxy S6 Edge.

In the 3DMark Ice Storm Unlimited, the ZenFone 2 was 253% faster than the ZenFone 5, but it was 10% slower than the Galaxy S6 Edge.

In AnTuTu, the ZenFone 2 was 105% faster than the ZenFone 5 and 25% slower than the Galaxy S6 Edge.
[nextpage title=”Main Specifications”]
The main specifications for the ASUS ZenFone 2 (model ZE551ML) include:

• Dimensions: 6.0 x 3.04 x 0.43 inches (152.5 x 77.2 x 10.9 mm)
• Weight: 6 ounces (170 grams)
• Display: 5.5 inches, 1920 x 1080, IPS touchscreen
• Operating System: Android 5.0 (“Lollipop”)
• Main Processor (CPU): Intel Atom Z3580, 2.3 GHz, four cores
• Graphics Processor (GPU): PowerVR G6430, embedded in the CPU
• RAM: 4 GiB
• Storage: 32 GiB (there are 16 GiB and 64 GiB versions too)
• Memory Card Slot: yes, MicroSD up to 128 GiB
• GPS: yes
• FM Radio: yes
• Sensors: accelerometer, proximity, light, gyro, compass
• SIM slots: two micro-SIM
• Networks: GSM/GPRS/EDGE 850/900/1800/1900 MHz, UMTS/HSPA+ 900/2100 MHz, 4G LTE 1700/1800/1900/2100 MHz
• Wi-Fi: IEEE 802.11b/g/n/ac
• Bluetooth:  yes, 4.0
• Rear camera: 13 Mpixel
• Front camera: 5 Mpixel
• Flash: yes, dual tone
• Battery talk time: not informed
• Battery: 3.7 V, 3,000 mAh Li Ion, not removable
• More information: https://www.asus.com/
• Average price in the U.S.*: USD 300.00

* Researched at Newegg.com in the day this review is published.
[nextpage title=”Conclusions”]
Launched last year, the ZenFone 5 was intended to be a smartphone with great cost/benefit ratio. In that, it was successful. Now, ASUS launches this new device, the ZenFone 2, which is very superior to its predecessor, not even being a replacement or a competitor in market. While the ZenFone 5 is a mainstream smartphone, the ZenFone 2 is close, in terms of hardware, to the top shelf smartphones on the market, with a lower cost.
The highlights os the ASUS ZenFone 2 are the Full HD screen, the fast CPU and the excellent cameras.
Strong Points

• Great cost/benefit ratio
• Big screen with Full HD resolution
• Sturdy
• Great design
• Excellent performance
• 5 MP front camera
• 13 Mp rear camera
• Supports microSD memory card
• Support for two SIM cards
• Supports 4G LTE
• Supports NFC
• Fast battery charge

Weak Points

• Could be thinner
• Does not record movies at 60 fps or at 4K