2018 iPad Pro Models Could Have Very Fast Octa-Core A11X Bionic Chip

Apple's next-generation iPad Pro models released in 2018 will feature octa-core processors, based on Taiwanese supplier TSMC's improved 7nm manufacturing process, according to Chinese website MyDrivers.

iPad Pro with slim bezels and no Home button rendered by Benjamin Geskin

The report, citing sources within Apple's supply chain, claims the eight cores in the tentatively named A11X Bionic chip will include three high-performance "Monsoon" cores and five energy-efficient "Mistral" cores.

Like the A11 Bionic chip in the latest iPhone models, which is built on a 10-nanometer process, the A11X chip will reportedly feature TSMC's integrated fan-out wafer level packaging, or InFO WLP for short.

The chip will also presumably include a next-generation M11 coprocessor and neural engine for artificial intelligence tasks, such as processing facial recognition given rumors about Face ID on 2018 iPad Pro models.

The eight-core processor should unsurprisingly result in CPU performance improvements on next-generation iPad Pro models.

Our own Chris Jenkins provided an in-depth look at the architecture of Apple's A11 Bionic chip. He also highlighted details about TSMC's improved 7nm process and advanced InFO packaging process for 2018.

Apple's current 10.5-inch and 12.9-inch iPad Pro models have an A10X Fusion chip based on TSCM's 10nm fabrication process.

In addition to gaining Face ID, next-generation iPad Pro models are expected to have an iPhone X form factor with slimmer bezels and no Home button. However, the tablets will reportedly continue to have LCD displays due to yield rates.

Related Roundup: iPad Pro

Discuss this article in our forums

Apple Started Developing A11 Bionic Chip When A8 Chip Was Released Three Years Ago

Shortly after Apple's iPhone X event this week, the company's silicon chief Johny Srouji and marketing chief Phil Schiller sat down for an interview about its new A11 Bionic chip with Mashable's editor-at-large Lance Ulanoff.


One interesting tidbit mentioned was that Apple began exploring and developing the core technologies in the A11 chip at least three years ago, when the iPhone 6 and iPhone 6 Plus launched with A8 chips.
Srouji told me that when Apple architects silicon, they start by looking three years out, which means the A11 Bionic was under development when Apple was shipping the iPhone 6 and its A8 chip. Back then we weren't even talking about AI and machine learning at a mobile level and, yet, Srouji said, "The neural engine embed, it’s a bet we made three years ahead."
Apple's three-year roadmap can change if new features are planned, like the Super Retina HD Display in iPhone X.
"The process is flexible to changes," said Srouji, who’s been with Apple since the first iPhone. If a team comes in with a request that wasn't part of the original plan, "We need to make that happen. We don't say, 'No, let me get back to my road map and, five years later, I'll give you something."
Apple senior executives Phil Schiller, left, and Johny Srouji

In fact, Schiller praised Srouji's team for its ability to "move heaven and earth" when the roadmap suddenly changes.
"There have been some critical things in the past few years, where we've asked Johny's team to do something on a different schedule, on a different plan than they had in place for years, and they moved heaven and earth and done it, and it's remarkable to see."
A11 Bionic six-core chip has two performance cores that are 25 percent faster, and four high-efficiency cores that are 70 percent faster, than the A10 chip in iPhone 7 and iPhone 7 Plus. Early benchmarks suggest the A11 Bionic is even on par with the performance of Apple's latest 13-inch MacBook Pro models.

The A11 chip is more efficient at multi-threaded tasks thanks to a second-generation performance controller that is able to access all six of the cores simultaneously if a particular task demands it.
Gaming might use more cores, said Srouji, but something as simple as predictive texting, where the system suggests the next word to type, can tap into the high-performance CPUs, as well.
The A11 chip also has an Apple-designed neural engine that handles facial recognition for Face ID and Animoji, and other machine learning algorithms. The dual-core engine recognizes people, places, and objects, and processes machine learning tasks at up to 600 billion operations per second, according to Apple.
“When you look at applications and software, there are certain algorithms that are better off using a functional programming model,” said Srouji.

This includes the iPhone X’s new face tracking and Face ID as well as the augmented-reality-related object detection. All of them use neural networks, machine learning or deep learning (which is part of machine learning). This kind of neural processing could run on a CPU or, preferably, a GPU. “But for these neural networking kinds of programming models, implementing custom silicon that’s targeted for that application, that will perform the exact same tasks, is much more energy efficient than a graphics engine,” said Srouji.
Apple's new iPhone 8, iPhone 8 Plus, and iPhone X are all equipped with an A11 chip.

In related news, Carnegie Mellon University's School of Computer Science has announced that Srouji will take part in a distinguished industry lecture on Monday, September 18 from 5:00 p.m. to 6:30 p.m. local time.

Full Interview: The Inside Story of the iPhone X 'Brain,' the A11 Bionic Chip


Discuss this article in our forums

A11 Chip’s 6-Core Architecture Highlights Apple’s Continuing Push Into Heterogeneous Computing

In the recent leak of information from Apple, a device tree shared by Steven Troughton-Smith and containing information specific to the iPhone X was used to glean CPU code names, presence of an OLED display, and information on many other things. Contained within that information were also specific details regarding the architecture behind Apple's new CPU cores, dubbed "Mistral" and "Monsoon." From this, we know that the A11 contains four Mistral cores and two Monsoon cores, and it's worth taking a technical look at what Apple might be up to with this new chip.

Leaked A11 chip

While the two Monsoon cores are clear follow-ons to the two large "Hurricane" cores in the A10, the Mistral cores double the small core count of two "Zephyr" cores in the A10.

September 2016 event slide on the two Zephyr cores in the A10

Annotated die shots ultimately revealed that the small Zephyr cores appeared to be embedded within the larger Hurricane cores, taking advantage of their geographic location by sharing memory structure with the Hurricane cores.

Chipworks/TechInsights annotated A10 die photo showing small Zephyr cores embedded within large Hurricane cores (right)

The Mistral cores appear to be a departure from the above scheme, at the very least in that they have doubled in count. Specific references in the device tree are also made to memory hierarchy, suggesting that they contain independent L2 caches, meaning the Mistral cores could be more independent than their A10 ancestors.

This independence is underscored by the fact that the Mistral cores share a common "cluster-id" property, while the Monsoon cores share a distinct cluster-id of their own. Immediate comparisons were drawn to ARM's big.LITTLE heterogeneous CPU core scheme with the A10, and this seems to be going further down that path with distinct operating states for each cluster of cores. However, those leveraged shared resources in the A10 were to a certain benefit, namely die space and power consumption. The cores becoming more independent is more like a traditional big.LITTLE approach, which also entails more overhead.

This all may be an oversimplification, of course. After all, we know that each of these CPU cores is independently addressable, meaning that nothing revealed so far indicates an active Mistral or Monsoon core (or cluster) precludes the other CPU type from also being active, opening the door for mixed processor scenarios. Apple could have decided to spend effort, either in hardware, compilers, or both, to segregate instructions by complexity and ultimately forward them to the core that would execute them mostly efficiently.

Tackling problems in this manner would be another example in a long list of Apple's attempts to improve instruction execution efficiency through microarchitecture enhancements.

Any architectural changes ultimately circle back to improvements in some way. If Apple is making a change that includes doubling the amount of lower power cores, it seems inevitable it's ultimately spending more die space to do so, particularly if they have their own cache structures from L2 and down.

Yet, as pointed out by AnandTech editor Ian Cutress, ARM has begun allowing for configurable cache sizes for its offering of cores. In this specific case, a non-existent L2 cache is a valid configuration, meaning the increase in die space may not be as much as it initially seems with the small core count growth.

It's important to remember that Apple is not bound to these ARM conventions, but they are an indication of where the industry is headed. It's also important to remember that the shared L3 cache is always sitting above all of the cores, along with the GPU and image signal processor. Ultimately, these architectural changes likely boil down to a performance per watt increase, instructions per clock cycle increase, or perhaps both. Given that the small tasks a Mistral core might be activated for would likely not expose the parallelism needed for all four cores, it seem some interesting usage scenarios are a strong likelihood with Apple's A11 SoC.

To give the mixed-core ensemble of the A11 context, modern CPUs aggressively manage performance and power consumption by dynamically changing clock speeds, processor voltages, and even disabling entire CPU cores by gating clocks and powers to these cores. There are numerous references to all of these concepts in the software, in addition to several references of dynamic CPU and core control, as well as instructions per clock cycle, memory throughput thresholds, power thresholds, and even hysteresis to keep the cores from spinning up and down as the performance profile changes. No doubt many of these properties existed in the A10 as well, but the fact that Apple is increasing small core count shows Apple believes there's more benefit to be had here.

Reference to "bcm4357" in iPhone X device tree

There are more details contained than just the CPU and OLED display, however. The software specifically calls out Broadcom's BCM4357 as the Wi-Fi module. This is curious because the BCM4357 is actually a very old Wi-Fi chipset. It seems likely that Apple truncated the trailing 0 from the BCM43570, which fits the 802.11ac profile of the iPhone 7 (and thus, not an upgrade). However, Broadcom does have a BCM4375 chip on the horizon which supports the forthcoming 802.11ax standard. Unless the keynote specifically addresses the Wi-Fi speeds, we may not immediately get clarification here, given the Wi-Fi module is often embedded in a larger module, often by component integrator Murata.

Moving over to the display side, the peak brightness in nits property seems to be referenced to a full scale value, rather than an actual decimal nits value, unfortunately. This could have given insight into whether Apple sought to pursue any of the existing HDR standards on the market, which often require a peak brightness over 1000 nits.

In the audio realm, the CS35L26 reference confirms another Cirrus Logic win for the top and bottom speakers, and the CS42L75 is an undocumented audio codec. Finally, for pure trivia, there's a reference to a 'sochot' property that curiously references the A6X chip identifier. It also contains an 'N41' reference in the baseband section, which refers to an iPhone 5 codename that introduced LTE to the iPhone families. These may, however, simply be references to old devices when features or properties were first introduced.

Apple will undoubtedly reveal some details on the new A11 chip and other internal upgrades for the new iPhones at its event that's just a few hours away now, but other information will have to wait until teardown firms can get their hands on the devices and have a closer look at what's inside.

Tag: A11 chip

Discuss this article in our forums