The A9 features an Apple-designed 64-bit 1.85 GHz The A9 also features a custom
PowerVR Series7XT @ 650 MHz GPU, featuring 6x custom shader cores and compiler from Apple. The A9 includes a new
image processor, a feature originally introduced in the
A5 and last updated in the
A7, with better temporal and spatial noise reduction as well as improved local tone mapping. The A9 directly integrates an embedded
M9 motion
coprocessor, a feature originally introduced with the
A7 as a separate chip. In addition to servicing the accelerometer, gyroscope, compass, and barometer, the M9 coprocessor can recognize
Siri voice commands. H.264,
MPEG‑4, and
Motion JPEG. The A9 features a custom storage solution, which uses an Apple-designed
NVMe-based controller that communicates over a
PCIe connection. The iPhone 6s' NAND design is more akin to a PC-class SSD than embedded flash memory common on mobile devices. This gives the phone a significant storage performance advantage over competitors which often use
eMMC or
UFS to connect to their flash memory.
Microarchitecture The A9's
microarchitecture is similar to the second generation Cyclone (used in A8 chip) microarchitecture. Some of the microarchitectural features are as follows: About half of the performance boost over A8 comes from the 1.85 GHz frequency. About a quarter comes from the better memory subsystem (3× bigger caches). The remaining quarter comes from the microarchitectural tuning.
Encryption According to Apple, "Every iOS device has a dedicated AES-256 crypto engine built into the DMA path between the flash storage and main system memory, making file encryption highly efficient. On A9 or later A-series processors, the flash storage subsystem is on an isolated bus that is only granted access to memory containing user data via the DMA crypto engine."
Dual sourcing (Chipgate) Apple A9 chips are
fabricated by two companies:
Samsung and
TSMC. The Samsung version is called APL0898, which is manufactured on a 14 nm
FinFET process and is 96 mm2 large, while the TSMC version is called APL1022, which is manufactured on a 16 nm FinFET process and is 104.5 mm2 large. There was intended to be no significant difference in performance between the parts, but in October 2015, it was found that iPhone 6S models with Samsung-fabricated A9 chips consistently measured shorter battery life than those with TSMC-fabricated versions in CPU heavy usage; web browsing and graphics were not very different. Apple responded that "tests which run the processors with a continuous heavy
workload until the battery depletes are not representative of real-world usage", and said that internal testing combined with customer data demonstrated a variance of only 2–3%.
Naming While the Twister CPU core implements the ARMv8-A instruction set architecture licensed from
ARM Holdings, it is an independent CPU design and is unrelated to the much older but similarly named
Cortex-A9 and
ARM9 CPU that are designed by ARM themselves and implement the 32-bit
ARMv7-A and ARMv5E versions of the architecture.
Gallery The processors are nearly identical visually. The packaging have the same dimensions (approx 15.0×14.5 mm) and only superficial differences, like the designation text. Inside the packaging the silicon die differs in size. File:Apple A9 APL0898.jpg|APL0898, the Samsung version of the A9 File:Apple A9 APL1022.jpg|APL1022, the TSMC version of the A9 File:A9 APL0898 iPhone6s mlb 820-5507-A.jpg|A9 (APL0898) SoC on iPhone 6s main logic board File:A9 APL1022 iPhoneSE 082-00282.jpg|A9 (APL1022) SoC on iPhone SE main logic board
ARKit The A9 processor is listed as the minimum requirement for
ARKit. == Products that include the Apple A9 ==