“Apple A8X”的意思、由来-开放百科全书

The Apple A8X is a 64-bit ARM-based system on a chip (SoC) designed by Apple Inc. and manufactured by TSMC.^[2] It first appeared in the iPad Air 2, which was announced on October 16, 2014.^[7] It is a variant of the A8 inside the iPhone 6 family of smartphones and Apple states that it has 40% more CPU performance and 2.5 times the graphics performance of its predecessor, the Apple A7.^[7]^[8]

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.^[8] 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.^[1]

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, were designed.^[9] Instead the A8X in the iPad Air 2 uses an external 2 GB RAM module.^[1]^[9]

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.^[10]

Patent litigation

The A8X's branch predictor has been claimed to infringe on a 1998 patent.^[11]^[12] On October 14, 2015, a district judge found Apple guilty of infringing U.S. patent {{patent|US|5781752}}, "Table based data speculation circuit for parallel processing computer", on the Apple A7 and A8 processors.^[12] 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.^[13] On September 28, 2018, the ruling was overturned on appeal and the award thrown out by the U.S. Federal Circuit Court of Appeals.^[14] The patent expired in December 2016.^[15]

Products that include the Apple A8X

See also

References

1. ^¹²³⁴⁵iPad Air 2 Benchmark Points to A8X Chip With Triple-Core 1.5 GHz CPU, 2 GB RAM
2. ^¹²TSMC reportedly lands CPU orders for Apple next-generation iPad
3. ^The Samsung Exynos 7420 Deep Dive - Inside A Modern 14nm SoC
4. ^{{cite web |url=https://www.ifixit.com/Teardown/iPad+Air+2+Teardown/30592 |title=iPad Air 2 Teardown |publisher=iFixit |date=October 22, 2014 |accessdate=October 22, 2014}}
5. ^¹{{cite web |url=http://www.anandtech.com/show/8716/apple-a8xs-gpu-gxa6850-even-better-than-i-thought |title= Apple A8X’s GPU - GXA6850, Even Better Than I Thought |publisher=Anandtech |date=November 11, 2014 |accessdate=November 12, 2014}}
6. ^{{cite web |url=http://www.notebookcheck.net/Imagination-PowerVR-GXA6850.128993.0.html |title= Imagination PowerVR GXA6850 - NotebookCheck.net Tech |publisher=NotebookCheck.net |date=November 26, 2014 |accessdate=November 26, 2014}}
7. ^¹{{cite press release |url=https://www.apple.com/pr/library/2014/10/16Apple-Introduces-iPad-Air-2-The-Thinnest-Most-Powerful-iPad-Ever.html |title=Apple Introduces iPad Air 2—The Thinnest, Most Powerful iPad Ever |publisher=Apple |date=October 16, 2014 |accessdate=October 16, 2014}}
8. ^¹{{cite web |url=https://www.apple.com/ipad-air-2/performance/ |title=iPad Air 2 - Performance |publisher=Apple |date=October 16, 2014 |accessdate=October 16, 2014}}
9. ^¹Latest iPad Air 2 component leak shows A8X chip & 2GB RAM
10. ^{{cite web |url=http://www.anandtech.com/show/8716/apple-a8xs-gpu-gxa6850-even-better-than-i-thought |title=A8X's GPU - Even Better Than I Thought |publisher=Anandtech |date=November 11, 2014 |accessdate=September 3, 2015}}
11. ^{{cite web |url=https://www.theregister.co.uk/2014/02/04/cupertino_copied_processor_pipelining_claims_wisconsin_u/ |title=Cupertino copied processor pipelining claims Wisconsin U |last1=Chirgwin |first1=Richard |date=February 4, 2014 |website=www.theregister.co.uk |publisher=The Register |accessdate=February 3, 2014}}
12. ^¹{{cite news|url=https://arstechnica.com/tech-policy/2015/10/apple-faces-862m-patent-damage-claim-from-university-of-wisconsin/|title=Apple faces $862M patent damage claim from University of Wisconsin|author=Joe Mullin|date=October 14, 2015|accessdate=October 14, 2015|publisher=Ars Technica}}
13. ^{{Cite news|url=https://www.reuters.com/article/ip-patent-apple/apple-urges-appeals-court-to-toss-506-million-patent-loss-to-warf-idUSL2N1N12RW|title=Apple urges appeals court to toss $506 million patent loss to WARF|last=Wolfe |first=Jan |publisher=Reuters |date=October 26, 2017 |access-date=February 22, 2018}}
14. ^{{cite news |url=https://www.reuters.com/article/us-apple-decision-patent/apple-wins-reversal-in-university-of-wisconsin-patent-lawsuit-idUSKCN1M81TV |title= Apple wins reversal in University of Wisconsin patent lawsuit |last=Stempel |first=Jonathan |publisher=Reuters |date=September 28, 2018 |accessdate=November 17, 2018}}
15. ^{{cite news |url=https://www.reuters.com/article/us-ip-apple-patent-idUSKBN1AB023 |title=Apple ordered to pay $506 million to university in patent dispute |last=Wolfe |first=Jan |publisher=Reuters |date=July 25, 2017 |accessdate=July 26, 2017}}