Over the weekend, the first iPhone 5 benchmarks have started to appear on Geekbench. The results, if they’re real, highlight two very interesting facts: The new core inside the A6 SoC is Apple’s own creation, rather than a Cortex-A9 or A15; and despite the new core, the latest dual and quad-core Android devices are just as fast, or faster.
The “iPhone5,2” – officially known as model number A1429 – scores 1601 on Geekbench. According to Geekbench, the iPhone 5 has two ARMv7 cores clocked at 1.02GHz, 1GB of RAM, and the same caches as the A5 (32KB L1 instruction, 32KB LA data, 1MB L2). The iPhone 4S (A5 SoC) has an average Geekbench score of around 600, so the iPhone 5 is more than twice as fast – which tallies with Apple’s performance claims.
To put the iPhone 5/A6 in context: The quad-core Galaxy S III (Exynos 4 Quad, a Cortex-A9 design) has a Geekbench score of around 1800; the dual-core One X (U.S. version, Snapdragon S4, Krait) scores around 1600; and the quad-core Nexus 7 (Tegra 3, Cortex-A9) scores around 1600.
We must also bear in mind that Geekbench makes full use of multiple cores, which gives the quad-core chips an unfair advantage – after all, there are few if any smartphone apps that make good use of four cores.
The iPhone 5′s benchmarks have two standout features: The A6 is clocked very low (just 1GHz, versus the 1.4GHz and 1.5GHz chips in most other smartphones), and its memory performance is out of this world. Compared to the 4S (Cortex-A9), the iPhone 5 has somewhere in the region of three to five times better memory performance. Even compared to a newer chip, such as the Snapdragon S4, the A6 is still almost twice as fast.
Despite the low clock speed, the A6′s dual-core CPU still has between two and three times the theoretical performance of the A5, again tallying with Apple’s claim of double the performance. The Snapdragon S4 has slightly better integer and floating point performance, but at a much higher clock speed (1.5GHz). It is the A6′s low clock speed and excellent performance that suggests that Apple has designed its own core, rather than using a beefed-up Cortex-A9 or new Cortex-A15. Anandtech is also confirming, through its own research, that the A6 indeed features a custom CPU core.
The benchmarks suggest that the A6 core is similar to Krait – which is wider than Scorpion (the previous Snapdragon S3 core), but without deepening the pipeline. A wider out-of-order architecture allows for an increase in IPC (instructions per clock), but without driving the clock speed (and thus power consumption) up. Remember, Apple has also increased battery life from the iPhone 4S to the iPhone 5, which is partly thanks to Qualcomm’s single-chip 28nm radio and the shift to 32nm on the A6, but there’s undoubtedly some funky stuff going on inside the SoC too.
Two questions remain: If the A6 SoC does contain a custom-made CPU core, why didn’t Apple advertise that fact during the keynote presentation? Furthermore, why did Apple design its own core anyway?
I can only guess at the answer to the first question. It could be that Apple is sworn to secrecy through a licensing deal (maybe Qualcomm designed the core for Apple?), or that it’s working on patenting the design. It’s possible that yields of the chip (which we presume are being made on Samsung’s 32nm process) are low, and that only some iPhone 5s will have the new core inside.
As to why Apple designed its own core, the answer is fairly simple: Apple is a control freak. Its previous SoCs, the A4, A5, and A5X, used conventional Cortex cores – but otherwise they were heavily customised. Designing its own CPU core was just the next logical step.
With its own core, and perhaps its own instruction set extensions, Apple can ensure that iOS 6 and the A6 are perfectly synergistic, further increasing performance and lowering battery consumption. There is also the possibility that the Cortex-A15 simply doesn’t provide the power efficiency that Apple requires, forcing the company to design its own core that is both efficient and quick.
Want to read more on how the iPhone 5 stacks up to the high-end competition? Then check out our series of head-to-head spec comparisons. There’s the iPhone 5 vs. the Nokia Lumia 920 here, and the Galaxy S III here, then there’s also the Galaxy Note 2, and finally the HTC One X.
You can win an iPhone 5 in our iPhone 5 competition by answering a simple question about what generation the Phone 5 is. Check ITProPortal live report on Apple’s announcement. Other than theiPhone 5, we saw new iPod devices but no cheaper version of the iPhone 4S, an iPad mini and potentially a 13in Macbook Pro with Retina Display.
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