Apple A8X

Apple A8X SoC

The Apple A8X is one of the US company Apple developed and the Taiwanese company TSMC manufactured system on a chip (SoC). It combines a 64-bit - ARM - CPU with a graphics processor and main memory . The A8X bears the internal name APL 1012 and is the first SoC from Apple that has three processor cores and 2 GB of RAM .

history

After the A8, the A8X is the second SoC manufactured by TSMC for Apple. The manufacturer of the predecessor SoCs was Samsung . Years of company disputes preceded the move from Samsung to TSMC. Still, Samsung continues to make older chips for Apple. The A8X was presented by Apple on October 16, 2014 as part of the iPad Air 2 and is supported by the M8 sensor coprocessor .

The A8X's processor incorporates technology that is patented by the University of Wisconsin . As a result, the company has to pay $ 234 million in damages for patent infringement.

technology

The A8X chip with the name APL 1012 installed in the iPad Air 2 has three RISC processor cores clocked at 1.5  GHz that support the 64-bit ARMv8 instruction set and are downward compatible with the 32-bit ARMv7 and ARMv6 instruction set. The micro- architecture called Typhoon is an in-house development by Apple. Compared to the first Cyclone generation, it achieves 16 percent higher processing power (IPC, instructions per clock cycle); the clock frequency increased by only 8 percent compared to the Apple A7 of the iPad Air (S5L8965).

The A8X addresses 2 GB SDRAM memory (LPDDR3), which is clocked at 1600 MHz, via a 64-bit wide address bus. The A8X is manufactured at TSMC using the 20SOC process. The changed manufacturing process means that three billion transistors fit on the chip. A PowerVR Series6XT modified by Apple with eight shader clusters is used as the GPU .

Due to the higher performance of the A8X (Apple states 40% more computing power and 250% more graphics performance compared to the predecessor A7), the A8X, like the predecessors A5X , A6X and S5L8965, has a metallic heat spreader that counteracts the increased heat dissipation through better heat dissipation.

At 128 bits, the memory interface is twice as wide as with the A8 , and measurements have also shown that the L2 cache is twice as large with 2 MB as with the A8 .

Microarchitecture

Block diagram of Apple's second generation 64-bit Cyclone CPU.

The processor cores of the Apple A8X were not licensed by Apple directly from ARM , but by means of a so-called ARM architecture license, which u. a. and the chip maker Qualcomm for its Snapdragon - SoCs uses, as a successor to the Cyclone CPU from the Apple A7 developed. Since Apple hardly publishes any technical information about Cyclone itself, there is only limited reliable information about the microarchitecture.

Electronics editor Frank Riemenschneider tried to draw conclusions about the micro-architecture of Cyclone using information published by Apple, an iPhone 6 and apps he developed himself . The block diagram of the second Cyclone generation presented is the only one of its kind published to date.

Individual evidence

1. ↑ Various authors in The Huffington Post : Apple Samsung Lawsuit , various release dates between 2012 and 2014, accessed October 22, 2014
2. ↑ Patent dispute: Apple sentenced to US university to pay damages. $ 234 million for stolen patents: Apple has to pay fine to the University of Wisconsin. The affected technology can also be found in various iPhone versions. In: ZEIT ONLINE. ZEIT ONLINE GmbH, October 18, 2015, accessed on October 18, 2015 . 
3. ↑ Ryan Smith: More on Apple's A9X SoC . in AnandTech . November 30, 2015
4. ↑ Frank Riemenschneider on Elektroniknet: New engine for iPhone 6: The photo proves Apple A8 with GPU PowerVR GX6450 , September 10, 2014, accessed on September 23, 2014
5. ↑ ^{a b} Frank Riemenschneider on Elektroniknet: Apple-A8X with triple-core CPU and improved storage system , October 22, 2014, accessed on November 11, 2014
6. ↑ Sebastian Anthony on Extreme Tech : Apple's A8 SoC analyzed: The iPhone 6 chip is a 2-billion-transistor 20nm monster , published on September 10, 2014, accessed on September 17, 2014 (English)
7. ↑ Ryan Smith: Apple A8X's GPU - GXA6850, Even Better Than I Thought. On: Anandtech. November 11, 2014, accessed January 18, 2015.
8. ↑ Frank Riemenschneider : Second Cyclone generation is the most powerful ARM CPU of all time. Report to Elektroniknet.de from September 30, 2014.