A15 wins first place, but cannot cover up Apple iPhone's problems

The iPhone 13 arrived as expected, but the new features did not become the focus. Even the A15 Bionic processor that Apple is proud of, which outperforms its competitors by 50%, has received a relatively indifferent response from the outside world. Instead, the new color scheme and price reduction of the iPhone 13 have attracted a lot of attention. This is indeed not good news for a company that is loved by many people for its innovation.

This makes people wonder why the A15 Bionic, which Apple calls "the fastest smartphone chip", is no longer competing with its "predecessor" A14? Does the performance of Apple's A15 really surpass Qualcomm's flagship Snapdragon 888 by as much as 50%? Is the A series processor, the cornerstone of iPhone functional innovation, still worth looking forward to in the future?

Apple rarely gives 50% performance lead data

At the iPhone 13 launch conference, Apple confidently stated, "In fact, the industry is still struggling to catch up with our chip performance. Not to mention last year's chips, or even our chips from two years ago." But in fact, Apple's confidence is largely due to its partner TSMC.

The A15 chip uses TSMC's 5nm process and integrates a total of 15 billion transistors. The CPU adopts a 6-core design (2 performance cores + 4 efficiency cores). The GPU has two versions: 4-core (iPhone13/iPhone13mini) and 5-core (iPhone13 Pro/Pro Max). It integrates a new ISP, video encoder and decoder, and the system cache has doubled.

Apple introduced that compared with its competitors, the CPU performance of A15 is 50% higher than that of its competitors, the quad-core GPU of A15 is 30% higher than that of its competitors, and the 5-core GPU of A15 is 50% higher than that of its competitors. In addition, the NPU performance reaches 15.8TOPS, which is 43.6% higher than the 11 TOPS of A14.

Apple did not specify which version of the 5nm process the A15 uses, but considering the evolution of TSMC's products, Apple may be using the N5P node. According to TSMC's commitment, processors using the N5P process will increase frequency by up to 5%, or reduce power consumption by up to 10%, and increase density by 1.8 times.

Thanks to TSMC's new process, the number of transistors in the A15 has reached 15 billion, an increase of 27% from the 11.8 billion in the A14. This is also the rare clear information currently available about the comparison between the A14 and A15.

Apple's move is somewhat surprising. In the past, when Apple released a new generation of products, it would directly give the performance improvement compared to the previous generation of processors, and in a few cases, it would also give a comparison with competitors.

This time, not only did Apple not give the performance improvement of A15 compared to the previous generation, it also did not specify the competitors for comparison. This should be a compromise choice based on comprehensive considerations.

"Before there is a major breakthrough in battery and system power consumption, it will be difficult for mobile phones to have breakthrough innovations similar to the previous generations of iPhone. When Apple cannot disclose the layout of its unreleased new products, the best explanation it can give to the capital market is chips. This may be one of the reasons why Apple only gave the performance gap compared to its competitors this time." Uncle J, a veteran in the chip industry, said.

"The process technology determines the upper limit of CPU performance." Two industry experts told Leifeng.com, "Without a significant improvement in the process technology, the difference in chip performance will only be limited to one order of magnitude."

In other words, Apple needs to tell the outside world about its leadership. The leading chip performance is an important message, but the CPU improvement of A15 is not impressive enough. Only announcing a performance gap with competitors can take both into account.

Uncle J analyzed, "In the current mobile phone chip market, Huawei Kirin rarely appears in the open market. MediaTek is still in a state of catching up with cost performance as the main focus. The only company that can compare with Apple is Qualcomm. This is actually a main battlefield for the competition between the Android camp and iOS."

Foreign media anandtech also believes that the competitor of A15 mentioned by Apple is Qualcomm, and the comparison is Qualcomm's 2020 flagship product Snapdragon 888. Looking at the SPECint2017 benchmark test results, the performance of A14 is 41% higher than that of Snapdragon 888. In other words, if A15 widens the gap to 50%, it means that A15 only needs to improve by 6% over A14, which is indeed not an upgrade worthy of separate announcement.

After the release of iPhone 13, benchmark data of A15 appeared in the GeekBench database, showing that the single-core performance of A15 increased by 8% and the multi-core performance increased by about 11%.

Compared with the limited improvement of CPU, the GPU has been significantly improved. After the release of iPhone 13, the testing software Geekbench showed GPU running points, which was 55% higher than A14.

At this point, it is easier for us to understand that even if the GPU performance has been greatly improved, the CPU performance has remained almost the same, and Apple has no reason to promote the improvement of A15 over A14 at the press conference. It is a good slogan to declare that Apple A15 is also 50% more powerful than Snapdragon 888.

How is Apple A15 better than Snapdragon 888?

"Apple uses this year's products to compare Qualcomm's products last year, and this comparison itself does not have a high reference value." Uncle J pointed out. As for the CPU and GPU, which can achieve a performance advantage of up to 50%, the process is actually more important. The three chip experts all said: "For the same Arm architecture CPU, Apple's understanding is better than Qualcomm's. In fact, the performance of the CPU has little to do with the design, and the key is still the process."

"The A15's GPU performance has a 50% advantage, but it also does not reflect that Apple is superior in chip design. If Qualcomm stacks up the number of GPU cores, the performance can be the same as Apple. The real strength is on the same order of magnitude." Uncle J further pointed out.

A senior person with more than ten years of experience in chip IP and EDA believes that "this is also an important reason why the market is almost indifferent even if Apple claims to have a 50% performance advantage."

Therefore, from the perspective of chip design and performance alone, Apple's 50% performance advantage is not impressive. The real reason why Apple wins is the difference between iOS software and hardware collaboration and Android + Qualcomm separation. Apple's real advantage lies in its control over the system and ecosystem, which is difficult for Qualcomm to achieve in the huge Android camp. The fact that the A15 has two different GPU core numbers is a good example.

The A15 GPU has two versions, 4 cores and 5 cores. It is not common for the same model to use different GPU core counts, but Apple can vary it for different products. An important feature of this year's iPhone13 Pro/Pro Max is the movie effect mode, which can automatically or manually change the focus of the video and guide the audience's vision through virtual and real changes, just like the focus switching within the same scene in movie shooting. Currently, only Apple in the industry can achieve such a function.

"Using the movie effect mode means that the phone needs to collect a lot of visual information and perform various high-computation processing, and also render it in real time, which places very high demands on the GPU." Uncle J said, "Application scenarios like this are the important reasons why the A15 needs to have 5 GPU cores."

But the iPhone 13 with a 4-core GPU also supports this feature. This is not difficult to understand. The Pro series phones have three cameras and the screen has higher performance and supports ProMotion adaptive refresh rate. Compared with the iPhone 13 with only two cameras and no adaptive refresh rate support, it is reasonable to use fewer GPU cores. In addition, at the product level, Pro users are more likely to use this feature, so redundancy is also needed in performance.

Moreover, this does not pose any design challenges to Apple. "Chips on a wafer can be divided into several grades according to their yield, and chip manufacturers can launch different grades of products based on the performance under different yields." Uncle J believes that "Apple can design the GPU of A15 according to 5 cores, and after manufacturing, select the part with only 4 cores with a yield as the 4-core version of A15, or turn off one GPU core of the GPU with all 5 cores working through software, and the cost will remain the same."

In addition to GPU, AI performance can also reflect Apple's advantages in chip design. In addition to CPU and GPU, AI is also critical for functions such as movie effect mode and text recognition on pictures on iPhone. Judging from the performance figures alone, the AI ​​performance of Snapdragon 888 is 32TOPS, while the latest A15 is only 15.8TOPS. The AI ​​performance of Snapdragon 888 is nearly twice that of A15.

Previously, an AI ISP expert told Leifeng.com that "no one can use the 32TOPS AI performance on the Snapdragon 888. Although the Snapdragon 888 has such capabilities, if it really runs at the highest AI performance, power consumption becomes a big problem."

"Qualcomm needs to take into account the AI ​​algorithm requirements of mobile phone manufacturers such as Xiaomi, OPPO, and VIVO, and it is even more difficult to make trade-offs between performance, cost, and power consumption." Uncle J said, "Apple can maximize AI performance, and Qualcomm has to be redundant."

The key reason behind this is the control over the ecosystem, which is the core reason why the performance of Apple and Qualcomm processors has gradually shown obvious differences. The reason for today's situation is the slowdown of Moore's Law.

What's the future of Apple processors?

A senior person in chip IP and EDA said: "The improvement of semiconductor process has reached its limit, and the performance of mobile phone processors is already in excess. When the process is difficult to improve, it also means that the era of pure hardware competition is over. At this time, all performance is cost, and how to reduce power consumption becomes the key."

This is almost a consensus in the industry. Another chip industry expert also said, "Due to the slowdown in process upgrades, the overall focus of the A series chips is to improve energy efficiency."

In terms of improving the energy efficiency of mobile phone processors, system companies have advantages that pure mobile phone chip design companies cannot surpass. Mobile phone SoC is a typical heterogeneous system with CPU, GPU, NPU, etc.

"It's not that Qualcomm doesn't understand heterogeneous systems deeply enough. Heterogeneous systems need to be well integrated inside the chip. More importantly, the entire hardware system must be able to perform real-time dynamic optimization at the compilation level. This involves the task allocation mechanism, which is also a difficult problem of heterogeneous computing. Qualcomm needs to make compromises, while Apple only needs to optimize its own system." Uncle J pointed out.

Senior experts in chip IP and EDA also said, "Some software functions can be abstracted and implemented in hardware to improve performance, while some hardware functions require programmability and can be implemented in software, that is, software hardening and hardware softening. System companies like Apple can do this, but it is very difficult for Qualcomm."

It should be pointed out that the system cache size is also the key to system optimization. A senior person in chip IP and EDA said: "The current performance surplus refers to the excess computing performance. Increasing the cache can optimize the bandwidth. Apple has already tasted the sweetness in the M1 chip."

J said further that "in a heterogeneous system, the computing power of high-performance CPUs, GPUs, and AI cores cannot all be fully utilized. The communication and coordination between different cores, as well as the size and architecture of the cache and different scheduling strategies, all determine the performance of the processor."

NPU is another key in mobile phone processors. "The cost of NPU to achieve system differentiation is relatively low, and after the terminal has better AI performance, some tasks that need to be transmitted to the cloud can be processed on the terminal to meet the needs of more video, XR and other applications." Two industry experts hold the same view, "Of course, it is still necessary to balance the relationship between power consumption, so now NPU is pursuing energy efficiency Tops/W."

In other words, more attention needs to be paid to the energy efficiency of mobile phone processors in the future. At the same time, the improvement of mobile phone performance and functional innovation will rely more on system-level optimization. At this time, Apple has a clear advantage over Qualcomm. But it should be understood that Qualcomm and Apple are not competitors in essence.

"Qualcomm's profitability essentially comes from its patents in the communications field, while Apple's profitability mainly relies on its strong product capabilities and brand influence. No matter how powerful Apple is, I don't think the threat to Qualcomm is that great because it does not affect Qualcomm's core source of revenue." Uncle J said.

Will Apple abandon Qualcomm?

Senior experts in chip IP and EDA believe that it is possible, and baseband chips need to be developed and improved slowly. However, Uncle J believes that even if Apple develops baseband in the 5G era, it cannot avoid Qualcomm's patents in the communication field. Therefore, at least in the 5G era, this is of little significance to Apple. Developing 6G or satellite communication chips is more valuable to Apple.

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