CPU Performance

A Tale of Two SoCs

Unlike the mainstream smartphones which use storage capacity to differentiate the price points, ASUS has done a much more PC-like thing with their two Zenfone 2 models: the $100 upgrade not only provides the expected increase to storage capacity (64GB vs. 16GB), but all of the key specs are higher as well, starting with the SoC.

  Zenfone 2 64GB Zenfone 2 16GB Galaxy Note 4 Nexus 6 OnePlus One
SoC Intel Atom Z3580 Intel Atom Z3560 Exynos 5433 Snapdragon 805 Snapdragon 801
CPU Cores Quad-core
2.33 GHz
1.83 GHz
Quad-core A57 1.9 GHz
Quad-core A53 1.3 GHz
Quad-core Krait 450 2.7 GHz Quad-core Krait 400 2.5 GHz
GPU Cores PowerVR G6430 PowerVR G6430 Mali-T760 Adreno 420 Adreno 330
Screen 1920x1080 IPS LCD 5.5-in (408 ppi) 1920x1080 IPS LCD 5.5-in (408 ppi) 2560x1440 Super AMOLED 5.7-in (515 ppi) 2560x1440 AMOLED 5.96-in (493 ppi) 1920x1080 LTPS LCD 5.5-in (401 ppi)
Storage 64GB eMMC
MicroSD Slot (up to 64GB)
MicroSD Slot (up to 64GB)
MicroSD Slot (up to 128GB)
32/64 GB eMMC 16/64 GB eMMC
Camera 13MP Rear
5MP Front
13MP Rear
5MP Front
16MP Rear
2MP Front
13MP Front
2MP Front
5MP Front
Battery 11.4 Whr
3000 mAh
11.4 Whr
3000 mAh
12.4 Whr
3220 mAh
12.2 Whr
3220 mAh
11.8 Whr
3100 mAh

SIM 1: Intel XMM7262 (Cat 6 LTE)
SIM 2: Intel XMM2230 (GSM)

SIM 1: Intel XMM7262 (Cat 6 LTE)
SIM 2: Intel XMM2230 (GSM)
Ericsson M7450 LTE (Cat 4) Qualcomm MDM9x25 UE Category 4 LTE Qualcomm MDM9x25 UE Category 4 LTE

802.11a/b/g/n/ac (2.4/5 GHz)
Bluetooth 4.0, USB 2.0

802.11a/b/g/n/ac (2.4/5 GHz)
Bluetooth 4.0, USB 2.0
802.11a/b/g/n/ac (2.4/5 GHz)
Bluetooth 4.1
USB 2.0
802.11a/b/g/n/ac (2.4/5 GHz)
Bluetooth 4.1
USB 2.0
802.11a/b/g/n/ac (2.4/5 GHz)
Bluetooth 4.1
USB 2.0
OS Android 5.0 Android 5.0 Android 4.4.4 Android 5.0.1 Android 4.4.4

To quickly compare, the $199 Zenfone 2 is equipped with a quad-core Intel Atom Z3560 SoC, a 22 nm part with a max burst speed of 1.83 GHz, along with 2 GB of 1600 MHz LPDDR3 and 16 GB of storage onboard. And here’s where things get very PC: the $299 model not only gets you 64 GB of local storage capacity, but a faster Intel Atom Z3580 SoC with a 2.33 GHz burst speed, a massive 4 GB of memory, and Intel’s own version of rapid charging ("BoostMaster"), which offers similar performance to the Qualcomm Quick Charge 2.0 technology found on devices with Snapdragon SoCs.

We were provided with both versions of the Zenfone 2, and though the higher-end $299 model was used for my impressions Ryan benchmarked the $199 version to see if there was a measurable difference between these SoCs (and total amount of system memory).

Let's jump right in to see how these Intel processors performed.

CPU Benchmarks

Geekbench 3

Geekbench 3 is Primate Labs' cross-platform processor benchmark, with a new scoring system that separates single-core and multi-core performance, and new workloads that simulate real-world scenarios. Geekbench 3 makes it easier than ever to find out if your computer is up to speed. Every test in Geekbench 3 is multi-core aware. This allows Geekbench to show you the true potential of your system. Whether you're running Geekbench on a dual-core phone or a 32-core server, Geekbench is able to measure the performance of all the cores in your system.

Geekbench acts much like a traditional synthetic processor benchmark would, giving us an idea of the peak performance that the CPU offers in both integer and floating point math.

A strong showing here for Samsung's international version of the Galaxy Note 4, which uses the Exynos 5433 SoC (with its 8-core big.LITTLE processor). The Samsung SoC has a huge lead in integer performance with both single and multi-core, with the 64GB Zenfone 2 coming in just behind the Nexus 6. This is also our first look at how much the clock speed difference between the two Zenfone 2 versions will effect performance, and this test certainly scaled with clock speed.

It's the same story with the floating-point test, and another big win for the Exynos processor. It will be interesting to benchmark additional big.LITTLE SoCs going forward. As is stands the Zenfone 2's both outperformed the Snapdragon 801 in the OnePlus One, with the exception of single-threaded performance from the 16GB Zenfone 2's Atom Z3560, which was the lowest of this group with both benchmarks.

Google Octane

Octane 2.0 is a modern benchmark that measures a JavaScript engine’s performance by running a suite of tests representative of today’s complex and demanding web applications. Octane‘s goal is to measure the performance of JavaScript code found in large, real-world web applications, running on modern mobile and desktop browsers.

The updated Octane 2.0 benchmark includes four new tests to measure new aspects of JavaScript performance, among which: garbage collection / compiler latency and asm.js-style JavaScript performance.

Our testing with Google Octane was done exclusively on the latest version of the Chrome browser on Android.

Very impressive showing from the Intel Atom SoCs with Google's JavaScript benchmark, particularly with the faster Z3580 processor. From the performance disparity it's clear that these new Atom SoCs love higher clocks, making the $299 version of this phone seem like a significant improvement for $100 more; especially considering the unlocked prices of the other phones in this test.

Mozilla's JavaScript benchmark tells the same story, with the phones finishing in exactly the same order and another sizeable win for the Z3580 processor.


This is SunSpider, a JavaScript benchmark. This benchmark tests the core JavaScript language only, not the DOM or other browser APIs. It is designed to compare different versions of the same browser, and different browsers to each other.

This test mostly avoids microbenchmarks, and tries to focus on the kinds of actual problems developers solve with JavaScript today, and the problems they may want to tackle in the future as the language gets faster. This includes tests to generate a tagcloud from JSON input, a 3D raytracer, cryptography tests, code decompression, and many more examples. There are a few microbenchmarkish things, but they mostly represent real performance problems that developers have encountered.

This test is balanced between different areas of the language and different types of code. It's not all math, all string processing, or all timing simple loops. In addition to having tests in many categories, the individual tests were balanced to take similar amounts of time on currently shipping versions of popular browsers.

One of the challenges of benchmarking is knowing how much noise you have in your measurements. This benchmark runs each test multiple times and determines an error range (technically, a 95% confidence interval). In addition, in comparison mode it tells you if you have enough data to determine if the difference is statistically significant.

Our testing with SunSpider was done exclusively on the latest version of the Chrome browser on Android.

The 16GB Zenfone 2 lost a step in this test to the Nexus 6, but the faster Z3580 in the 64GB version leads this final JavaScript benchmark by the same wide margin as the first two. These are the lowest numbers I've seen from an Android phone in JavaScript benchmarks so far, but let's see how these Atom SoCs perform under some mixed browser workloads.


WebXPRT 2013 uses scenarios created to mirror the tasks you do every day to compare the performance of almost any Web-enabled device. It contains four HTML5- and JavaScript-based workloads: Photo Effects, Face Detect, Stocks Dashboard, and Offline Notes.

Once again the Zenfone 2's finished 1, 2 at the top of the list, with the Nexus 6 and Note 4 trading places in the middle of the pack. So far these Atom SoCs look very impressive, despite a weaker showing in the initial synthetic CPU tests.


Brought to you by the independent industry association, EEMBC (www.eembc.org) – developing industry-standard benchmarks since 1997.

Allows device vendors to assess performance, drive competitive analysis, and accomplish stability testing
Empowers end-users to validate and compare capabilities of their phones or tablets
Compare your benchmark results with other uploaded results at our website - www.eembc.org/andebenchpro.php
Automated statistical analysis for minimum, median, and maximum values
Focuses on the key metrics that reflect the most common usage models of Android devices

Hardware tests exercise CPU, GPU, memory, and storage
Platform tests target common application services including GUI rendering, XML parsing, image operations, cryptography

The AndEBench-Pro results have more in common with the Geekbench 3 tests than the JavaScript benchmarks, and with the exception of the CoreMark test the 16GB Zenfone 2 was at the bottom of the pack. The 1.83 GHz speed of the Z3560 processor just can't keep up under these workloads, with far better results coming from the Z2580 at 2.33 GHz. The Note 4 and Nexus 6 traded victories here, but the 64GB Zenfone 2 wan't far behind.

Next we'll look at GPU performance.

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