Asus Zenfone 2 review: A balancing act

A balancing act

GSMArena team, 14 April, 2015.

Intel inside

The entire Zenfone 2 range is powered by Intel Atom chipsets, and the ZE551ML we have at the office has an Atom Z3560 SoC with its quad-core processor clocked anywhere between 500MHz and 1.83GHz, depending on the work load.

Update, June 11: We have added the benchmark scores of the range-topping Asus ZenFone 2 with 4GB of RAM. In addition to more memory, it packs a more powerful Intel Atom Z3580 SoC with 2.3 GHz quad-core CPU. For comparison, Asus ZenFone 2 with 2GB of RAM features Intel Atom Z3560 with 1.8GHz quad-core CPU.

The 4GB Asus ZenFone 2 delivered mostly impressive performance across the board, leaving many flagship devices behind it on more than one occasion. As expected, the 4GB variant is also noticeably faster than its sibling with 2GB of RAM.

Asus Zenfone 2 ZE551ML

Intel's offerings can hardly impress with numbers in the Android realm, where higher-clocked octa-core processors have become the norm. However, the Atom Z3560 proved to be able to compete with the Snapdragon 800 and its quad-core 2.26GHz processor, back when we reviewed the Asus Memo Pad ME572C, a similarly specced tablet.

Our review unit comes with 2GB of RAM, which should be about enough for smooth daily usage. Demanding power users, who do a lot of multitasking may choose to go with the top model that comes with 4GB and the faster Atom Z3580, albeit at a price premium.

We tried to pick a few of the Zenfone 2's market rivals, which are frankly hard to pinpoint, but also threw in the current crop of flagships to see how it compares to the leading performers out there.

We'll start with the CPU centric Geekbench 3.0 test. As expected, the Zenfone 2 doesn't impress with raw CPU performance and is miles behind the 1.7GHz octa-core Meizu m1 note. The Samsung Galaxy Note 3 with S800 together with the Oppo Find 7a and OnePlus One both powered by S801 are ahead as well. Still, the Zenfone 2 manages to inch ahead of both LG G2 and G3 and is superior to the Galaxy Note 3 Neo.

GeekBench 3

Higher is better

  • Samsung Galaxy S6
    5215
  • Meizu m1 note
    3988
  • HTC One M9
    3761
  • LG G Flex2
    3604
  • Meizu MX4
    3556
  • Samsung Galaxy Note 4 Lollipop
    3394
  • Xiaomi Mi Note
    3094
  • Oppo Find 7a
    3093
  • Samsung Galaxy Note 3 S800
    2937
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    2922
  • Samsung Galaxy A7 (S615)
    2880
  • OnePlus One
    2663
  • LG G Pro 2
    2585
  • Xiaomi Redmi Note
    2435
  • Asus Zenfone 2 ZE551ML
    2423
  • LG G3
    2370
  • LG G2
    2243
  • Samsung Galaxy Note 3 Neo
    2172
  • HTC Desire 816
    1510

Antutu 5 adds RAM and storage speed into the mix and is an indication of the overall performance of the device. The Zenfone 2 delivers a strong performance, on par with the Galaxy Note 3 with S800 and the LG G3 with S801.

AnTuTu 5

Higher is better

  • Samsung Galaxy S6
    69396
  • HTC One M9
    51427
  • Samsung Galaxy Note 4 Lollipop
    49273
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    48361
  • LG G Flex2
    47680
  • Meizu MX4
    46922
  • Xiaomi Mi Note
    45632
  • Asus Zenfone 2 ZE551ML
    42301
  • Samsung Galaxy Note 3 S800
    42211
  • LG G3
    42038
  • Meizu m1 note
    39224
  • Xiaomi Redmi Note
    32487
  • Samsung Galaxy A7 (S615)
    31436

The even broader Basemark OS II benchmark continues the trend. Overall, the Zenfone 2 performs well, if far from the top of the current flagship crop. Again, the Galaxy Note 3 and G2 remain behind.

As expected though, the CPU focused parts of the benchmark weren't the Atom's strong suit and it was bolted to bottom of the comparison charts.

Basemark OS II

Higher is better

  • Samsung Galaxy S6
    1769
  • LG G Flex2
    1601
  • HTC One M9
    1526
  • Xiaomi Mi Note
    1370
  • Samsung Galaxy Note 4 Lollipop
    1332
  • LG G3
    1327
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    1267
  • OnePlus One
    1196
  • LG G Pro 2
    1140
  • Asus Zenfone 2 ZE551ML
    1094
  • Oppo Find 7a
    1057
  • Samsung Galaxy Note 3 S800
    1003
  • LG G2
    848
  • Samsung Galaxy A7 (S615)
    786
  • Meizu m1 note
    715
  • Meizu MX4
    695
  • HTC Desire 816
    520
  • Xiaomi Redmi Note
    452

Basemark OS II (single-core)

Higher is better

  • Samsung Galaxy S6
    3497
  • Oppo Find 7a
    2580
  • Samsung Galaxy Note 4 Lollipop
    2574
  • Xiaomi Mi Note
    2559
  • LG G Flex2
    2528
  • HTC One M9
    2401
  • LG G Pro 2
    2401
  • LG G3
    2267
  • Samsung Galaxy Note 3 S800
    2236
  • OnePlus One
    2213
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    1853
  • Meizu m1 note
    1754
  • HTC Desire 816
    1739
  • Meizu MX4
    1729
  • Xiaomi Redmi Note
    1701
  • Samsung Galaxy A7 (S615)
    1572
  • Asus Zenfone 2 ZE551ML
    1462

Basemark OS II (multi-core)

Higher is better

  • Samsung Galaxy S6
    16986
  • Meizu m1 note
    12848
  • Xiaomi Redmi Note
    12771
  • Meizu MX4
    12268
  • Oppo Find 7a
    10256
  • OnePlus One
    10234
  • HTC One M9
    10128
  • LG G3
    9975
  • LG G Pro 2
    9802
  • LG G Flex2
    9758
  • Xiaomi Mi Note
    9590
  • Samsung Galaxy Note 3 S800
    9364
  • Samsung Galaxy A7 (S615)
    9284
  • Samsung Galaxy Note 4 Lollipop
    9198
  • HTC Desire 816
    7071
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    7002
  • Asus Zenfone 2 ZE551ML
    5600

In the graphics department, the Zenfone 2 is equipped with a PowerVR G6430 GPU as Intel doesn't make its own graphics chips for the Atoms. It's a somewhat old GPU, released back in Q3 2013, made by British semiconductor manufacturer Imagination Technologies. It was featured in Apple's A7 SoC inside the iPhone 5S, and is chosen by Intel for the entire range of Z35xx Atoms.

GFXBench returned the same results in both the off-screen and on-screen routines, not exactly surprising, having in mind that the standardized off-screen tests are carried out at 1080p resolution, the same as the actual one on the Zenfone 2.

The GPU puts out solid numbers in the T-Rex test beating the Galaxy Note 3 and the LG G3 and G2. Even the Galaxy Note 4 is a frame behind in the on-screen test, but don't forget its QHD resolution. The more intense Manhattan routine halves the framerate but even so the Zenfone 2 posts great results. Apart from the Galaxy S6 and the Snapdragon 810s, no one proves to be a match.

GFX 2.7 T-Rex (1080p offscreen)

Higher is better

  • Samsung Galaxy S6
    59
  • HTC One M9
    49
  • LG G Flex2
    49
  • Samsung Galaxy Note 4 Lollipop
    40
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    30
  • Oppo Find 7a
    28.4
  • OnePlus One
    28.3
  • Xiaomi Mi Note
    28
  • Asus Zenfone 2 ZE551ML
    27
  • Samsung Galaxy Note 3 S800
    26.3
  • LG G3
    26
  • LG G Pro 2
    22.9
  • Meizu MX4
    22.7
  • LG G2
    22
  • Samsung Galaxy A7 (S615)
    15
  • Meizu m1 note
    15
  • Samsung Galaxy Note 3 Neo
    15
  • Xiaomi Redmi Note
    9.8
  • HTC Desire 816
    5.9

GFX 2.7 T-Rex (onscreen)

Higher is better

  • HTC One M9
    50
  • LG G Flex2
    48
  • Samsung Galaxy S6
    38
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    30
  • OnePlus One
    30
  • Oppo Find 7a
    28.8
  • Xiaomi Mi Note
    28
  • Asus Zenfone 2 ZE551ML
    27
  • Samsung Galaxy Note 3 S800
    26.7
  • Samsung Galaxy Note 4 Lollipop
    26
  • Samsung Galaxy Note 3 Neo
    25
  • LG G Pro 2
    24.1
  • LG G2
    23.1
  • Meizu MX4
    21.3
  • LG G3
    20
  • Meizu m1 note
    16
  • Samsung Galaxy A7 (S615)
    15
  • Xiaomi Redmi Note
    13.3
  • HTC Desire 816
    11

GFX 3.0 Manhattan (1080p offscreen)

Higher is better

  • Samsung Galaxy S6
    24
  • HTC One M9
    23
  • LG G Flex2
    22
  • Samsung Galaxy Note 4 Lollipop
    18
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    13
  • Asus Zenfone 2 ZE551ML
    13
  • OnePlus One
    12.1
  • Oppo Find 7a
    11.4
  • LG G3
    11
  • Xiaomi Mi Note
    11
  • Samsung Galaxy Note 3 S800
    9.9
  • LG G Pro 2
    8.7
  • Meizu MX4
    7.9
  • Samsung Galaxy A7 (S615)
    5.8
  • Meizu m1 note
    5.8
  • Samsung Galaxy Note 3 Neo
    3.7
  • HTC Desire 816
    1.7

GFX 3.0 Manhattan (onscreen)

Higher is better

  • HTC One M9
    24
  • LG G Flex2
    22
  • Samsung Galaxy S6
    14
  • Asus Zenfone 2 ZE551ML
    13
  • OnePlus One
    12.9
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    12
  • Oppo Find 7a
    11.4
  • Xiaomi Mi Note
    11
  • Samsung Galaxy Note 4 Lollipop
    11
  • Samsung Galaxy Note 3 S800
    10
  • LG G Pro 2
    9.2
  • LG G3
    7.7
  • Meizu MX4
    7.4
  • Samsung Galaxy A7 (S615)
    5.8
  • Meizu m1 note
    5.7
  • Samsung Galaxy Note 3 Neo
    4.7
  • HTC Desire 816
    3.9

Basemark X is a bit less flattering on the Zenfone, but in this company it still performs admirably. Of the old dogs only OnePlus One is ahead, and not by much.

Basemark X

Higher is better

  • Samsung Galaxy S6
    27169
  • Samsung Galaxy Note 4 Lollipop
    20043
  • HTC One M9
    19848
  • LG G Flex2
    19360
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    13414
  • OnePlus One
    13129
  • Xiaomi Mi Note
    13075
  • Asus Zenfone 2 ZE551ML
    12565
  • LG G2
    11101
  • LG G3
    10580
  • Meizu MX4
    8324
  • Samsung Galaxy A7 (S615)
    4802
  • Meizu m1 note
    4617
  • Xiaomi Redmi Note
    2974
  • HTC Desire 816
    1437

Browser performance turned out very good as well. The JavaScript-intense Kraken 1.1 squeezed a 6360ms score from the Zenfone 2, the best result behind the obvious powerhouses. HTML5 is a non-issue too, as evidenced by the figures in BrowserMark 2.1.

Kraken 1.1

Lower is better

  • Samsung Galaxy S6
    4154
  • LG G Flex2
    4621
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    5057
  • Samsung Galaxy Note 4 Lollipop
    5181
  • HTC One M9
    5500
  • Asus Zenfone 2 ZE551ML
    6360
  • Xiaomi Mi Note
    6382
  • LG G Pro 2
    6578
  • Oppo Find 7a
    6660
  • OnePlus One
    7008
  • LG G3
    7632
  • Meizu MX4
    9408
  • Samsung Galaxy A7 (S615)
    12266
  • Xiaomi Redmi Note
    12416
  • HTC Desire 816
    13564
  • Meizu m1 note
    15055

BrowserMark 2.1

Higher is better

  • Samsung Galaxy S6
    2718
  • Samsung Galaxy Note 4 Lollipop
    2232
  • LG G Flex2
    2086
  • Asus ZenFone 2 ZE551ML (4GB of RAM)
    1853
  • HTC One M9
    1681
  • Samsung Galaxy A7 (S615)
    1655
  • Asus Zenfone 2 ZE551ML
    1486
  • LG G3
    1453
  • LG G Pro 2
    1346
  • OnePlus One
    1339
  • Oppo Find 7a
    1327
  • HTC Desire 816
    774
  • Xiaomi Mi Note
    748
  • Meizu MX4
    720
  • Xiaomi Redmi Note
    588
  • Meizu m1 note
    536

To wrap up, the Zenfone 2 ZE551ML proves to be a strong performer, even in this compromise configuration with 2GB of RAM and Intel Atom Z3560. While it may not be on par with the latest and greatest, it outperforms established flagship names from the previous generation and shows no apparent weaknesses. We can only imagine what the top model would have shown in these tests with double the operating memory and higher maximum clock speed.

Reader comments

  • Anonymous
  • 20 Jun 2021
  • JEf

the asus zen fone 2 is good in you life

Any chance to upgrade this phone to Android Nouget, guys? (Unofficial upgrade of course) Direct me to link please..! Mine is Z00AD version. Thanks

  • Anonymous
  • 14 Nov 2017
  • CGH

Calibrate your battery using the root method