 Apple A9 processor | |
| General information | |
|---|---|
| Launched | September 9, 2015 |
| Discontinued | September 12, 2018 |
| Designed by | Apple Inc. |
| Common manufacturer | |
| Product code | APL0898,[1] APL1022[2] |
| Performance | |
| Max.CPUclock rate | 1.85 GHz (iPhone 6s, iPhone 6s Plus, iPhone SE, iPad 9.7 2017)[3][4] |
| Cache | |
| L1cache | Per core: 64 KB instruction + 64 KB data |
| L2 cache | 3 MB shared[5] |
| L3 cache | 4 MB shared[6] |
| Architecture and classification | |
| Application | Mobile |
| Technology node | 14 nm (Samsung 14LPE), 16 nm (TSMC 16FFC) |
| Microarchitecture | Twister[7][8] |
| Instruction set | ARMv8-A:A64,A32,T32 |
| Physical specifications | |
| Cores |
|
| GPU | CustomPowerVR Series 7XT (six-core) @ 650MHz[9][10][11] |
| Products, models, variants | |
| Variant | |
| History | |
| Predecessors | Apple A8 (iPhone) Apple A8X (iPad) |
| Successors | Apple A10 Fusion (iPhone) Apple A10X Fusion (iPad) |
TheApple A9 is a64-bitARM-basedsystem-on-chip (SoC) designed byApple Inc., part of theApple silicon series. Manufactured for Apple by bothTSMC andSamsung, it first appeared in theiPhone 6s and 6s Plus which were introduced on September 9, 2015.[12] Apple states that it has 70% more CPU performance and 90% more graphics performance compared to its predecessor, theApple A8.[12] On September 12, 2018, theiPhone 6s and iPhone 6s Plus along with thefirst-generation iPhone SE was discontinued, ending production of A9 chips. The latest software updates for theiPhone 6s & 6s Plus including theiPhone SE (1st generation) variants systems using this chip areiOS 15.8.4, released around August, 2024, as they were discontinued with the release ofiOS 16 in 2022, and for theiPad (5th generation) using this chip wasiPadOS 16.7.10, also released on September 3, 2024, as it was discontinued with the release ofiPadOS 17 in 2023.
The A9 features an Apple-designed 64-bit 1.85 GHz[3] ARMv8-A dual-core[5] CPU calledTwister.[8] The A9 in the iPhone 6s has 2 GB ofLPDDR4 RAM included in the package.[1][5] The A9 has a per-coreL1 cache of 64KB for data and 64 KB for instructions, anL2 cache of 3MB shared by both CPU cores, and a 4 MB L3 cache that services the entire SoC and acts as avictim cache.[6] The A9 also features a customPowerVR Series7XT @ 650 MHz GPU, featuring 6x custom shader cores and compiler from Apple.[13]
The A9 includes a newimage processor, a feature originally introduced in theA5 and last updated in theA7, with better temporal and spatial noise reduction as well as improved local tone mapping.[14] The A9 directly integrates an embeddedM9 motioncoprocessor, a feature originally introduced with theA7 as a separate chip. In addition to servicing the accelerometer, gyroscope, compass, and barometer, the M9 coprocessor can recognizeSiri voice commands.[14]
The A9 has video codec encoding support forH.264. It has decoding support forHEVC,[15] H.264,MPEG‑4, andMotion JPEG.[16]
The A9 features a custom storage solution, which uses an Apple-designedNVMe-based controller that communicates over aPCIe connection.[17] 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 useeMMC orUFS to connect to their flash memory.
The A9'smicroarchitecture is similar to the second generation Cyclone (used in A8 chip) microarchitecture. Some of the microarchitectural features are as follows:
| Pipeline depth (stages) | 16 |
|---|---|
| Issue width | 6 micro-ops |
| ROB | 196 micro-ops |
| Load latency | 8 cycles |
| Branch misprediction penalty | 9 |
| Number of integer pipes | 4 |
| Number of shifter ALUs | 4 |
| Load/Store Units | 2 |
| Integer pipe buffer size | 48 |
| Number of branch units | 2 |
| Indirect branch units | 1 |
| Branch pipe buffer size | 24 |
| FP ALUs | 3 |
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.[citation needed]
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."[18]
Apple A9 chips arefabricated by two companies:Samsung andTSMC. The Samsung version is called APL0898, which is manufactured on a 14 nmFinFET 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,[19] 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.[20] Apple responded that "tests which run the processors with a continuous heavyworkload 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%.[21][22]
While the Twister CPU core implements the ARMv8-A instruction set architecture licensed fromARM Holdings, it is an independent CPU design and is unrelated to the much older but similarly namedCortex-A9 andARM9 CPU that are designed by ARM themselves and implement the 32-bitARMv7-A and ARMv5E versions of the architecture.
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.
The A9 processor is listed as the minimum requirement forARKit.[23]
| Preceded by | Apple A9 2015 | Succeeded by |