The Apple A8 is a

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A comp ...

ARM-based

system on a chip A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memor ...

(SoC) designed by Apple Inc. It first appeared in the iPhone 6 and

iPhone 6 Plus The iPhone 6 and iPhone 6 Plus are smartphones that were designed and marketed by Apple Inc. They are the List of iOS devices, eighth generation of the iPhone, succeeding the iPhone 5, iPhone 5C and iPhone 5S, and were announced on September ...

, which were introduced on September 9, 2014. Apple states that it has 25% more CPU performance and 50% more graphics performance while drawing only 50% of the power of its predecessor, the Apple A7. The latest software updates for the 1.1GHz and 1.4GHz variants systems using this chip are iOS 12.5.6, released on August 31, 2022 as they were discontinued with the release of iOS 13 in 2019, and 1.5GHz variant for the iPad Mini 4 is iPadOS 15.7.1, released on October 27, 2022 as it was discontinued with the release of iPadOS 16 in 2022, while updates for the 1.5GHz variant continue for Apple TV HD. The A8 chip was discontinued on October 18, 2022, following the discontinuation of the Apple TV HD.

Design

The A8 is manufactured on a

20 nm NM, nm, and variations may refer to: Businesses and organizations * Northwestern Mutual, financial services company in Wisconsin, United States * Air Madrid (IATA airline designator NM), Spanish airline * Mount Cook Airline (IATA airline des ...

process by

TSMC Taiwan Semiconductor Manufacturing Company Limited (TSMC; also called Taiwan Semiconductor) is a Taiwanese multinational semiconductor contract manufacturing and design company. It is the world's most valuable semiconductor company, the world' ...

, which replaced

Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...

as the manufacturer of Apple's mobile device processors. It contains 2 billion transistors. Despite having twice the number of transistors of the A7, the A8's physical size has been reduced by 13% to . The A8 uses LPDDR3-1333 RAM on a 64-bit memory interface; in the iPhone 6/6 Plus, sixth generation

iPod Touch The iPod Touch (stylized as iPod touch) is a discontinued line of iOS-based mobile devices designed and marketed by Apple Inc. with a touchscreen-controlled user interface. As with other iPod models, the iPod Touch can be used as a music pl ...

, and

HomePod The HomePod is a smart speaker developed by Apple Inc. The HomePod was designed to work with the Apple Music subscription service. The HomePod was announced on June 5, 2017, at the Apple Worldwide Developers Conference. Its launch was later de ...

, the A8 has 1 GB RAM included in the package. Meanwhile, the A8 in the iPad Mini 4 and 4th generation Apple TV is packaged with 2 GB RAM. The A8 CPU has a per-core L1 cache of 64 KB for data and 64 KB for instructions, an L2 cache of 1 MB shared by both CPU cores, and a 4 MB L3 cache that services the entire SoC. As its predecessor, it has a 6 decode, 6 issue, 9 wide, out-of-order design. The processor is dual core, and as used in the iPhone 6 has a frequency of 1.4 GHz, supporting Apple's claim of it being 25% faster than the A7. It also supports the notion of this being a second generation enhanced Cyclone core called Typhoon, and not an entirely new architecture which would supposedly mean a more significant performance gain per Hz. The A8 also integrates a

graphics processing unit A graphics processing unit (GPU) is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mo ...

(GPU) which is a 4-shader-cluster PowerVR Series 6XT. However the GPU features custom shader cores designed by Apple. On October 16, 2014, Apple introduced a variant of the A8, the A8X, in the iPad Air 2. Compared with the A8, the A8X has an enhanced 8-shader-cluster GPU and improved CPU performance due to one extra core and higher frequency. The A8 has video codec encoding support for H.264. It has decoding support for H.264, MPEG‑4, and Motion JPEG.

Patent litigation

The A8's

branch predictor In computer architecture, a branch predictor is a digital circuit that tries to guess which way a branch (e.g., an if–then–else structure) will go before this is known definitively. The purpose of the branch predictor is to improve the flow i ...

has been claimed to infringe on a 1998 patent. On October 14, 2015, a district judge found Apple guilty of infringing U.S. patent , "Table based data speculation circuit for parallel processing computer", on the Apple A7 and A8 processors. The patent is owned by Wisconsin Alumni Research Foundation (WARF), a firm affiliated with the

University of Wisconsin A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase ''universitas magistrorum et scholarium'', which ...

. On July 24, 2017, Apple was ordered to pay WARF $506 million for patent infringement. Apple filed an appellate brief on October 26, 2017, with the U.S. Court of Appeals for the Federal Circuit, that argued that Apple did not infringe on the patent owned by the Wisconsin Alumni Research Foundation. On September 28, 2018, the ruling was overturned on appeal and the award thrown out by the U.S. Federal Circuit Court of Appeals. The patent expired in December 2016.

Products that include the Apple A8

* iPhone 6 & 6 Plus *

iPod Touch (6th generation) The sixth generation iPod Touch (marketed as the iPod touch) is a mobile device designed and marketed by Apple Inc. with a touchscreen-based user interface. It is the successor to the iPod Touch (5th generation), becoming the first major upd ...

* iPad Mini 4 *

Apple TV An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancestor, ...

HD (formerly 4th generation) *

Gallery

Notes

References