Engineering:Apple A8

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Short description: System on a chip (SoC) designed by Apple Inc.
Apple A8
Apple A8 system-on-a-chip.jpg
Apple A8 processor
General Info
LaunchedSeptember 9, 2014
DiscontinuedPresent
Designed byApple Inc.
Common manufacturer(s)
Product codeAPL1011[2]
Performance
Max. CPU clock rate1.1 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))[3] 
Cache
L1 cachePer core: 64 KB instruction + 64 KB data[4]
L2 cache1 MB shared[4]
L3 cache4 MB[4]
Architecture and classification
ApplicationMobile
Min. feature size20 nm[5]
MicroarchitectureTyphoon[6][7]
Instruction setARMv8-A: [4]A64, A32, T32
Physical specifications
Transistors
  • 2 billion
Cores
GPU(s)Custom PowerVR Series 6XT (quad-core)[9][10]
Products, models, variants
Variant(s)Apple A8X
History
PredecessorApple A7
SuccessorApple A9

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.[11] 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,[12] and 1.5GHz variant for the iPad Mini 4 is iPadOS 15.7, released on September 12, 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.

Design

The A8 is manufactured on a 20 nm process[5] 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 (0.138 in2).[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.[2] Meanwhile, the A8 in the iPad Mini 4 and 4th generation Apple TV is packaged with 2 GB RAM.[13][14]

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.[4] 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.[15] It also supports the notion of this being a second generation[16] enhanced Cyclone core called Typhoon,[6][7] and not an entirely new architecture which would supposedly mean a more significant performance gain per Hz.[4]

The A8 also integrates a graphics processing unit (GPU) which is a 4-shader-cluster PowerVR Series 6XT.[17] However the GPU features custom shader cores designed by Apple.[10]

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 support of codecs by decoding and encoding is available only for JPEG. H264, VP-1 and AVC. HEVC 265 (8/10bit), VP8, VP9, AV1 are not supported by hardware. [18]

Patent litigation

The A8's branch predictor has been claimed to infringe on a 1998 patent.[19][20] On October 14, 2015, a district judge found Apple guilty of infringing U.S. patent US patent 5781752, "Table based data speculation circuit for parallel processing computer", on the Apple A7 and A8 processors.[20] 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. 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.[21] On September 28, 2018, the ruling was overturned on appeal and the award thrown out by the U.S. Federal Circuit Court of Appeals.[22] The patent expired in December 2016.[23]

Products that include the Apple A8

Gallery

A8 SoC on iPhone 6 main logic board.


See also

Notes

  1. ↑ Most analysts have reported that the Apple A8 is manufactured by TSMC, including Chipworks,[1] Techinsights,[24] and AnandTech.[25] An analyst at IHS reports that manufacturing is split, with TSMC manufacturing about 60 percent and Samsung manufacturing about 40 percent.[26]

References

  1. ↑ 1.0 1.1 1.2 "Inside the iPhone 6 and iPhone 6 Plus". Chipworks. September 19, 2014. http://www.chipworks.com/en/technical-competitive-analysis/resources/blog/inside-the-iphone-6-and-iphone-6-plus/. 
  2. ↑ 2.0 2.1 "iPhone 6 Plus Teardown". iFixit. September 18, 2014. https://www.ifixit.com/Teardown/iPhone+6+Plus+Teardown/29206. 
  3. ↑ "iPad Mini 4 performance preview: A 1.5GHz Apple A8 with 2GB of RAM". Ars Technica. September 15, 2015. https://arstechnica.com/apple/2015/09/ipad-mini-4-performance-preview-a-1-5ghz-apple-a8-with-2gb-of-ram/. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 "The iPhone 6 Review: A8's CPU: What Comes After Cyclone?". AnandTech. September 30, 2014. http://www.anandtech.com/show/8554/the-iphone-6-review/3. 
  5. ↑ 5.0 5.1 Smith, Ryan (September 9, 2014). "Apple Announces A8 SoC". AnandTech. http://www.anandtech.com/show/8504/apple-announces-a8-soc. 
  6. ↑ 6.0 6.1 "The Samsung Exynos 7420 Deep Dive - Inside A Modern 14nm SoC". http://anandtech.com/show/9330/exynos-7420-deep-dive/4. 
  7. ↑ 7.0 7.1 Chester, Brandon (July 15, 2015). "Apple Refreshes The iPod Touch With A8 SoC And New Cameras". http://www.anandtech.com/show/9443/apple-refreshes-the-ipod-touch-with-a8-soc-and-new-camera. 
  8. ↑ 8.0 8.1 Anthony, Sebastian. "Apple's A8 SoC analyzed: The iPhone 6 chip is a 2-billion-transistor 20nm monster". ExtremeTech. http://www.extremetech.com/computing/189787-apples-a8-soc-analyzed-the-iphone-6-chip-is-a-2-billion-transistor-20nm-monster. 
  9. ↑ Smith, Ryan (September 23, 2014). "Chipworks Disassembles Apple's A8 SoC: GX6450, 4MB L3 Cache & More". AnandTech. http://www.anandtech.com/show/8562/chipworks-a8. 
  10. ↑ 10.0 10.1 Kanter, David. "A Look Inside Apple's Custom GPU for the iPhone" (in en-US). https://www.realworldtech.com/apple-custom-gpu/. 
  11. ↑ "Apple Announces iPhone 6 & iPhone 6 Plus—The Biggest Advancements in iPhone History" (Press release). Apple. September 9, 2014. Archived from the original on September 9, 2014. Retrieved September 9, 2014.
  12. ↑ Savov, Vlad (September 9, 2014). "iPhone 6 and iPhone 6 Plus have a new faster A8 processor". The Verge (Vox Media). https://www.theverge.com/2014/9/9/6127111/iphone-6-and-iphone-6-plus-have-a-new-faster-a8-processor. 
  13. ↑ Chester, Brandon (September 9, 2015). "Apple Announces the iPad Pro and iPad Mini 4". AnandTech. http://www.anandtech.com/show/9615/apple-announces-the-ipad-mini-4. 
  14. ↑ "The New Apple TV". Apple Inc.. September 9, 2015. https://developer.apple.com/library/prerelease/tvos/documentation/General/Conceptual/AppleTV_PG/. 
  15. ↑ "Alleged iPhone 6 Geekbench Results Reveal 1.4 GHz Dual-Core A8 Chip, 1 GB of RAM". http://www.macrumors.com/2014/09/09/iphone-6-geekbench-1-4-ghz-dual-core-a8-1gb-ram/. 
  16. ↑ "Apple - iPhone 6 - Technology". https://www.apple.com/iphone-6/technology/. 
  17. ↑ "The iPhone 6 Review: A8's GPU: Imagination Technologies' PowerVR GX6450". AnandTech. September 30, 2014. http://www.anandtech.com/show/8554/the-iphone-6-review/4. 
  18. ↑ "Apple A8X vs. Apple A8 - Benchmark, Test und Technische Daten". https://www.cpu-monkey.com/de/compare_cpu-apple_a8x-1661-vs-apple_a8-1662. 
  19. ↑ Chirgwin, Richard (February 4, 2014). "Cupertino copied processor pipelining claims Wisconsin U". The Register. https://www.theregister.co.uk/2014/02/04/cupertino_copied_processor_pipelining_claims_wisconsin_u/. 
  20. ↑ 20.0 20.1 Joe Mullin (October 14, 2015). "Apple faces $862M patent damage claim from University of Wisconsin". Ars Technica. https://arstechnica.com/tech-policy/2015/10/apple-faces-862m-patent-damage-claim-from-university-of-wisconsin/. 
  21. ↑ Wolfe, Jan (October 26, 2017). "Apple urges appeals court to toss $506 million patent loss to WARF". Reuters. https://www.reuters.com/article/ip-patent-apple/apple-urges-appeals-court-to-toss-506-million-patent-loss-to-warf-idUSL2N1N12RW. 
  22. ↑ Stempel, Jonathan (September 28, 2018). "Apple wins reversal in University of Wisconsin patent lawsuit". Reuters. https://www.reuters.com/article/us-apple-decision-patent/apple-wins-reversal-in-university-of-wisconsin-patent-lawsuit-idUSKCN1M81TV. 
  23. ↑ Wolfe, Jan (July 25, 2017). "Apple ordered to pay $506 million to university in patent dispute". Reuters. https://www.reuters.com/article/us-ip-apple-patent-idUSKBN1AB023. 
  24. ↑ "Logic Detailed Structural Analysis of the 20 nm Node, TSMC Fabricated Apple A8 APL1011". Techinsights. August 28, 2015. http://www.techinsights.com/reports-and-subscriptions/open-market-reports/Report-Profile/?ReportKey=10664. 
  25. ↑ Ho, Joshua (November 2, 2015). "The Apple iPhone 6s and iPhone 6s Plus Review: Analyzing Apple A9's SoC". AnandTech. http://www.anandtech.com/show/9686/the-apple-iphone-6s-and-iphone-6s-plus-review/2. 
  26. ↑ Hesseldahl, Arik (September 23, 2014). "Teardown Shows Apple's iPhone 6 Cost at Least $200 to Build". Re/code. http://recode.net/2014/09/23/teardown-shows-apples-iphone-6-cost-at-least-200-to-build/. 
Preceded by
Apple A7 (APL0698 Variant)
 		Apple A8
2014 		Succeeded by
Apple A9




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