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Apple A8

Apple A8
Apple A8 system-on-a-chip.jpg
Apple A8 processor
Produced From September 9, 2014 to Present
Designed by Apple Inc.
Common manufacturer(s)
Max. CPU clock rate 1.1 GHz (iPod Touch 6th generation)  to 1.4 GHz (iPhone 6, iPhone 6 Plus) and 1.5 GHz (iPad mini 4 & Apple TV (4th Gen)) 
Min. feature size 20 nm
Instruction set A64, A32, T32
Microarchitecture TyphoonARMv8-A-compatible
Product code APL1011
Cores 2
L1 cache Per core: 64 KB instruction + 64 KB data
L2 cache 1 MB shared
L3 cache 4 MB
Predecessor Apple A7
Successor Apple A9
GPU PowerVR Series 6XT GX6450 (quad-core)
Application Mobile
Variant Apple A8X

The Apple A8 is a 64-bit ARM based system on a chip (SoC) designed by Apple Inc. It first appeared in the iPhone 6 and iPhone 6 Plus, 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 compared to its predecessor, the Apple A7.

The A8 is manufactured on a 20 nm process by TSMC, which replaced Samsung as the manufacturer of Apple's mobile device processors. It contains 2 billion transistors. Despite having twice the number of transistors compared to the A7, the A8's physical size has been reduced by 13% to 89 mm2. The A8 in the iPhone 6 and 6 Plus has 1 GB of LPDDR3 RAM included in the package, while the A8 in the iPad Mini 4 and 4th generation Apple TV is packaged with 2 GB of LPDDR3 RAM.

The A8 has a per-core L1 cache of 64 KB for data and 64 KB for instructions, a L2 cache of 1 MB shared by both CPU cores, and a 4 MB L3 cache that services the entire SoC.

Benchmarks suggest that the processor is dual core, and as used in the iPhone 6 has a frequency of 1.38 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 (GPU) which AnandTech believes to be a 4-cluster PowerVR GX6450.

On October 16, 2014, Apple introduced a variant of the A8, the A8X, in the iPad Air 2. Compared to the A8, the A8X has improved graphics and CPU performance due to one extra core and higher frequency.


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