The Apple A8X 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 ...
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. and manufactured 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' ...
.
It first appeared in the
iPad Air 2 and only is used in the iPad Air 2, which was announced on October 16, 2014.
It is a variant of the
A8 inside the iPhone 6 family of
smartphones
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
and Apple states that it has 40% more CPU performance and 2.5 times the graphics performance of its predecessor, the
Apple A7.
The latest software update for the iPad Air 2 using this chip was
iPadOS 15.7.1, released on October 27th 2022 as it was discontinued with the release of
iPadOS 16 in 2022 due to hardware limitations of the A8X.
Design
The A8X has three cores clocked at 1.5 GHz, a more powerful GPU compared to the A8 and it contains 3 billion transistors.
With an extra 100 MHz and an additional core, the A8X performs around 13% better on single threaded and 55% better on multithreaded operations than the A8 inside the iPhone 6 and iPhone 6 Plus.
Further comparison to the A8 shows that the A8X uses a metal
heat spreader, which the A8 does not, and it doesn't use the
package on package configuration with included
RAM which the A8 does. This is similar to how the older ''"X"'' variants, the
A5X and
A6X
The Apple A6X is a 32-bit system-on-a-chip (SoC) designed by Apple Inc., introduced at the launch of the 4th generation iPad on October 23, 2012. It is a high-performance variant of the Apple A6 and the last 32-bit chip Apple used on an iOS dev ...
, were designed.
Instead the A8X in the iPad Air 2 uses an external 2 GB RAM module.
In a first for Apple, the A8X is reported to have a semi-custom GPU. The A8X uses an 8-cluster GPU based on
Imagination Technologies PowerVR Series 6XT architecture. Officially, the largest implementation of Rogue is a 6-cluster design, indicating that Apple has made customizations to the design in order to provide higher performance. This GPU is referred to as the GXA6850, with the "A" denoting the Apple customization.
The A8X has video codec encoding support for
H.264. It has decoding support for H.264,
MPEG‑4, and
Motion JPEG.
Patent litigation
The A8X's
branch predictor 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. Universities typically offer both undergraduate and postgraduate programs. In the United Stat ...
. 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 A8X
*
iPad Air 2
See also
*
Apple silicon, the range of ARM-based processors designed by Apple.
*
Comparison of ARMv8-A cores
References
{{Application ARM-based chips
Computer-related introductions in 2014
Apple silicon
Products and services discontinued in 2022