Apple A8

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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))[2] 
Min. feature size 20 nm[3]
Instruction set A64, A32, T32
Microarchitecture Typhoon[4][5] ARMv8-A-compatible[6]
Product code APL1011[7]
Cores 2[8]
L1 cache Per core: 64 KB instruction + 64 KB data[6]
L2 cache 1 MB shared[6]
L3 cache 4 MB[6]
Predecessor Apple A7
Successor Apple A9
GPU PowerVR Series 6XT GX6450 (quad-core)[9]
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.[10] 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.[11]

Design[edit]

The A8 is manufactured on a 20 nm process[3] by TSMC,[1] which replaced Samsung 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 89 mm2.[8] The A8 uses LPDDR3-1333 RAM on a 64-bit memory interface; in the iPhone 6/6 Plus, sixth generation iPod touch and HomePod the A8 has 1 GB RAM included in the package,[7] while the A8 in the iPad Mini 4 and 4th generation Apple TV is packaged with 2 GB RAM.[12][13]

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.[6] 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.[14] It also supports the notion of this being a second generation[15] enhanced Cyclone core called Typhoon,[4][5] and not an entirely new architecture which would supposedly mean a more significant performance gain per Hz.[6]

The A8 also integrates a graphics processing unit (GPU) which is a 4-shader-cluster PowerVR GX6450.[16]

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.

Patent litigation[edit]

The A8's branch predictor has been claimed to infringe on a 1998 patent.[17][18] On October 14, 2015, a district judge found Apple guilty of infringing U.S. patent US 5781752 , "Table based data speculation circuit for parallel processing computer", on the Apple A7 and A8 processors.[18] The patent is owned by Wisconsin Alumni Research Foundation (WARF), a firm affiliated with the University of Wisconsin. On July 24, 2017, Apple was ordered to pay WARF $506 million for patent infringement. The patent expired in December 2016.[19] 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.[20]

Products that include the Apple A8[edit]

See also[edit]

Notes[edit]

  1. ^ Most analysts have reported that the Apple A8 is manufactured by TSMC, including Chipworks,[1] Techinsights,[21] and AnandTech.[22] An analyst at IHS reports that manufacturing is split, with TSMC manufacturing about 60 percent and Samsung manufacturing about 40 percent.[23]

References[edit]

  1. ^ a b c "Inside the iPhone 6 and iPhone 6 Plus". Chipworks. September 19, 2014. Archived from the original on 2014-09-24. Retrieved September 20, 2014. 
  2. ^ "iPad Mini 4 performance preview: A 1.5GHz Apple A8 with 2GB of RAM". Ars Technica. September 15, 2015. Retrieved September 16, 2015. 
  3. ^ a b Smith, Ryan (September 9, 2014). "Apple Announces A8 SoC". AnandTech. Retrieved September 9, 2014. 
  4. ^ a b The Samsung Exynos 7420 Deep Dive - Inside A Modern 14nm SoC
  5. ^ a b Chester, Brandon (July 15, 2015). "Apple Refreshes The iPod Touch With A8 SoC And New Cameras". Retrieved September 11, 2015. 
  6. ^ a b c d e f "The iPhone 6 Review: A8's CPU: What Comes After Cyclone?". AnandTech. September 30, 2014. Retrieved September 30, 2014. 
  7. ^ a b "iPhone 6 Plus Teardown". iFixit. September 18, 2014. Retrieved September 19, 2014. 
  8. ^ a b Anthony, Sebastian. "Apple's A8 SoC analyzed: The iPhone 6 chip is a 2-billion-transistor 20nm monster". www.extremetech.com. ExtremeTech. Retrieved 10 September 2014. 
  9. ^ Smith, Ryan (September 23, 2014). "Chipworks Disassembles Apple's A8 SoC: GX6450, 4MB L3 Cache & More". AnandTech. Retrieved September 23, 2014. 
  10. ^ "Apple Announces iPhone 6 & iPhone 6 Plus—The Biggest Advancements in iPhone History" (Press release). Apple. September 9, 2014. Retrieved September 9, 2014. 
  11. ^ Savov, Vlad (September 9, 2014). "iPhone 6 and iPhone 6 Plus have a new faster A8 processor". The Verge. Vox Media. Retrieved September 9, 2014. 
  12. ^ Chester, Brandon (September 9, 2015). "Apple Announces the iPad Pro and iPad Mini 4". AnandTech. Retrieved September 9, 2015. 
  13. ^ "The New Apple TV". Apple Inc. September 9, 2015. Retrieved September 9, 2015. 
  14. ^ Alleged iPhone 6 Geekbench Results Reveal 1.4 GHz Dual-Core A8 Chip, 1 GB of RAM
  15. ^ Apple - iPhone 6 - Technology
  16. ^ "The iPhone 6 Review: A8's GPU: Imagination Technologies' PowerVR GX6450". AnandTech. September 30, 2014. Retrieved September 30, 2014. 
  17. ^ Chirgwin, Richard (February 4, 2014). "Cupertino copied processor pipelining claims Wisconsin U". www.theregister.co.uk. The Register. Retrieved February 3, 2014. 
  18. ^ a b Joe Mullin (October 14, 2015). "Apple faces $862M patent damage claim from University of Wisconsin". Ars Technica. Retrieved October 14, 2015. 
  19. ^ Wolfe, Jan (July 25, 2017). "Apple ordered to pay $506 million to university in patent dispute". Reuters. Retrieved July 26, 2017. 
  20. ^ "Apple urges appeals court to toss $506 million patent loss to WARF". Reuters. 2017-10-26. Retrieved 2018-02-22. 
  21. ^ "Logic Detailed Structural Analysis of the 20 nm Node, TSMC Fabricated Apple A8 APL1011". Techinsights. August 28, 2015. Retrieved December 3, 2015. 
  22. ^ Ho, Joshua (November 2, 2015). "The Apple iPhone 6s and iPhone 6s Plus Review: Analyzing Apple A9's SoC". AnandTech. Retrieved December 3, 2015. 
  23. ^ Hesseldahl, Arik (September 23, 2014). "Teardown Shows Apple's iPhone 6 Cost at Least $200 to Build". Re/code. Retrieved December 1, 2015.