The A13 is a huge leap forward in architecture. Not that it is 20% faster, which is the least. It is the quantity of components and new small parts that help the whole in total as we have commented (if we use native development).
Apple's chip team will have been working for about 10 years, since April 2008 that Apple bought the company PA Semi and in January 2010 the first device with an own Apple chip was introduced: the iPad. This is the tenth chip they take out, if we don't count the X variations that have had some generations that only incorporate more CPU or GPU cores.
The Bionic A13, which has been improved in each and every component and added some new ones, is not just CPU. Now that we have had time to analyze we can see the following components:
High efficiency sound processor with 24-bit audio support. A DAC with advanced AAC or HE-AAC support, both version 1 and 2, is also capable of playing MP3, FLAC and many other audio formats. A processor that is also able to calculate the wave alterations of the spatial sound of the new iPhone, which creates a computational surround sound as HomePods do, together with the ability to decode a Dolby Atmos file, also supported at the sound level. And another function: it is able to extend the sound of a specific element of the sound spectrum. If I focus something on a video, what focuses and generates sound can increase the volume (zoom in on the sound) to that element that generates the sound.
Screen management processor and its frequency. We must not forget that the screen of the new iPhone Pro is the same as the Pro Display XDR monitor. It has an extended HDR mode, an average brightness of 800 nits with 1,200 peaks and a contrast of 1: 2,000,000. This processor establishes a dynamic refresh of the screen so that when some pixels do not change its content, its refreshment is less and with it improves the efficiency of the battery considerably. The Retina Pro XDR screen of the iPhone Pro does something similar and is capable of not sending a refresh signal to the screen if its content has not changed and thus save battery. Up to 15% higher energy efficiency than the XS or XS Max. It works in conjunction with an OLED display processing processor to manage the pixels and how they light up, which uses the Pro's screen engine to refresh or paint.
High performance unified memory processor. This is a technology that Nvidia uses in its CUDA library and in its GPUs. It basically allows you to access any part of the entire memory system and at the same time, migrate data on demand to the dedicated memory of each component with broadband access. In this way, in a single operation, the component that accesses a content in the general memory will obtain a migration of this direct data to its own memory area or registers.
HDR image processor, which is responsible for receiving the image and directly calculate the improved SmartHDR process. In this way, there is no CPU process and the treatment is instantaneous. That is why previous models cannot make this HDR improved: because a software algorithm that we can put on another computer does not: it does a chip that is specifically programmed for it.
Computer photography processor, which helps to interpret the content of the image and coordinate the processes that are carried out and the fusion operations, which entrusts them to another component that is responsible for receiving photos with instructions and calculating the fusion.
Processor of the components that are always on, and that must work in low energy mode. How to manage a Bluetooth connection when the device is locked, the GPS signal that enters constantly or the sound heard in the background. It allows not to use the entire CPU in operations that are understood should consume much less to be in the background.
Neural motor, which allows to run trained models of Machine Learning. All AI processes depend on it in terms of the process of neural, convolutional networks and all kinds of networks that process data and obtain probabilistic results.
Secure Enclave, an essential part of iPhone security. Save the biometric data, and encrypt and decrypt data transparently in a black box that never makes the encryption keys public if it does not return the encrypted data, as is. It also allows you to check the signature validation of any process. The A13 also has support for the Secure Enclave: a cryptographic calculation accelerator for decryption, encryption and faster calculations.
High-performance generic CPU cores, two specifically, at higher speeds and with greater capacity and performance. Dedicated to more complex operations that require more load.