Apple iPhone 5s performance review: CPU and GPU speed compared to top Android phones (benchmarks)

The Apple iPhone 5s is here and that means it’s time for some heavy duty benchmarking. 

The iPhone has traditionally been the go to device for games as Apple steps up the graphics every time, and this year is no exception. Starting last year, however, Apple is also designing the CPU processor cores on its own and does not simply rely on ARM designs. Cupertino did a great job with the Apple A6 system chip in the iPhone 5 where it integrated its own Swift processor core. Now, in Apple A7, we have a brand new processor core called Cyclone that is among the best out there. Let's take a look at it all in detail.

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CPU

First, let’s look at CPU performance. Let’s note that the Apple A7 is most likely a dual-core chip, with two Cyclone cores clocked at up to 1.3GHz. The whole chip is likely made on a 28nm HKMG process by Samsung, a step up from the 32nm chip in the iPhone 5.

It is also the first ever to use an ARMv8 64-bit design and that’s an important step forward. You’ve heard about that before, but let’s explain why this is important. The transition to 64-bit processors first started on desktops around 2005 with a clear goal to allow for more RAM. 32-bit systems are limited to supporting only around 3GB of RAM, and 64-bit systems allow for 4GB and more. However in Apple’s case that’s hardly the reason. The iPhone 5 used 1GB of LPDDR2 RAM and the iPhone 5S remains at 1GB but LPDDR3 RAM. It will be no less than 2 years until Apple needs 4GB of RAM. There thus must be another reason for Apple to move to 64-bit than RAM and there indeed is. Adopting the ARMv8 64-bit design comes with backwards 32-bit compatibility, but Apple’s software tools already allow for apps to be 64-bit aware. In a few years when Apple completes the 64-bit transition, this means it will already have a huge number of compatible apps. Other tangible improvements from the move to ARMv8 and 64-bit are the bigger number of general purpose registers, FP/NEON registers, and new SIMD instructions. iOS 7 itself and all included apps have already made the move to 64-bit.

The 1.3GHz clock speed might look low in comparison to top shelf Android devices, but keeping it relatively low allows for optimal power efficiency. The Cyclone core itself seems to be an evolution of the Swift core. In it, Apple has doubled L1 cache from 32KB/32KB (two separate caches for instruction and data) to 64KB/64KB. Level 1 cache is a static and very fast memory where often accessed data is stored, and it’s key to improving the overall and multitasking performance of a chip. L2 cache remains 1MB, but comes with faster access latency.

Now, on to the tests.

The first test we run is the Sunspider Javascript Benchmark that measures javascript performance. The iPhone 5s achieves around 75% better js performance than the iPhone 5, and easily tops the list beating even Cortex A15 competitors.


Mozilla Kraken is an even more stressful javascript benchmark. Sunspider’s popularity has forced companies to optimize their devices, and thus skew the picture, but there seems to be none of that in Kraken. Again, the iPhone 5s tops the charts with extremely fast js processing. The performance gain is more than double that of the iPhone 5.

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GPU

The iPhone has traditionally pushed the envelope for graphics and gaming including the best of Imagination Technologies’ graphical chips. This time, Apple has outdone itself and it has indeed included the newest PowerVR Series 6 chip with support for OpenGL ES 3.0. The particular chip is the PowerVR G6430 that makes the switch from a vector to a fully scalar architecture. It is a four-cluster chip that is advertized to deliver 2x the performance of the iPhone 5. In reality, the iPhone 5S probably delivers much more graphical oomph. Double the performance should be reached at around 200MHz, and Apple has likely clocked the G6430 much higher. 

Looking at the pure GFlops measurements, we see that Apple’s iPhone 5s is easily the most powerful platform currently available. The graphical performance of the iPhone 5s actually matched the iPad 4 at 76.8GFlops, and starts to approach console grade level. In comparison, gaming platforms like the Sony Playstation 3 score around 230GFlops. The currently available top shelf Android devices like the Samsung Galaxy S4 and the HTC One score around 50GFlops.

On to the benchmarks, we start with Basemark X 1.0. This test runs game simulations running on-screen and at 1080p off-screen. The test is very complex and that explains the low results, yet the iPhone 5s approached very closely the coveted 30fps.


GFXBench, formerly known as GL Benchmark, is one of the most GPU-intensive tests out there and it gives a detailed breakdown of a video card’s performance. Fill rates are the first thing we measure and you’d see that Apple managed to double the performance in the 5s compared to the iPhone 5. The 5s emerges as a clear leader, beating all existing devices.

Next comes the extremely heavy game simulation test in GFXBench - T-Rex HD. The iPhone 5s is the first device to actually break the 30fps barrier here and deliver smooth framerates at 35fps on-screen. The G6430 chip scores a 2.5x performance gain over the PowerVR SGX 543MP3 GPU in the iPhone 5.

The offscreen test shows how the G6430 compares with other platforms independent of a particular device. The G6430 still scores in the tops, but the Adreno 330 in a Snapdragon 800 configuration is close or bests it. The new Adreno 330 is expected to arrive in the Nexus 5 and we’re already seeing how the new Google handset will match or even beat the iPhone 5 in that department. The Nexus 5 GFXBench results have surfaced pre-maturely, and are not verified by us yet.

Conclusion

The Apple iPhone 5s brings is one of the biggest under-the-hood upgrades to ever happen to the iPhone line. Apple’s A7 chip comes with a new Cyclone core that is very well optimized in terms of power consumption and still manages to deliver great performance. It’s a dual-core unit, but we don’t yet seem to have enough optimized software to consider this a downside compared to other quad-core chips. Moreover, the A7 is the first 64-bit chip and that brings tangible advantages and opens up the opportunity for developers to build 64-bit aware apps much faster. Another plus for the great Apple ecosystem.

In terms of graphics, the Apple iPhone 5s is the new phone to beat. It comes with the new 6-series Imagination Technoligies’ GPU that delivers more than double the graphical punch of the iPhone 5 and comes with OpenGL ES 3.0 support. It is the first phone to deliver smooth over 30fps framerates on the most stressful graphical tests.

Overall, the A7 is an impressive chip. The average user will notice its incredible speed in loading webpages and how it resolves amazing detail in games. It’s future-proof. Now, if only Apple could listen and bring us all this in a similarly well designed package with a bit larger display...

reference: AnandTech, Chipworks