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What is an SoC? Everything you need to know about smartphone chipsets
Tech enthusiasts love to talk about processing power and chips, be it from PCs and gaming consoles to the latest smartphones. We do a fair bit of it here at Android Authority, with in-depth coverage of the latest processors from Arm, HUAWEI, Qualcomm, Samsung, MediaTek, and others. These topics are often dense with jargon and abstract-sounding ideas that can feel like a brick wall to understanding even basic questions like “What is an SoC?”
Indeed, it can take years of study to properly wrap your head around the finer details of chip design, which is no good if you’re simply trying to research a potential purchase. Today, we’re going to do something a bit more beginner-friendly and explain the ins and outs of modern smartphone chips with as little technical witchcraft as possible.
What is an SoC and what does it do?
SoC stands for system-on-a-chip. As the name suggests, an SoC is a complete processing system contained in a single package. To be clear, it isn’t just a singular processor, which you might be familiar with if you’ve ever built a PC. Instead, an SoC contains multiple processing parts, memory, modems, and other essential bits and pieces manufactured together in a single chip that’s soldered onto the circuit board.
The system-on-a-chip is the brain of your smartphone, handling everything from graphics to 5G connectivity.
Combining multiple components into a single chip saves on space, cost, and power consumption. Essentially, an SoC is the brain of your smartphone that handles everything from the Android operating system to detecting when you press the power off button. SoCs connect to other components too, such as cameras, a display, RAM, flash storage, and much more.
The list below contains the most common components that you will find inside a smartphone system-on-a-chip. We’re going to cover a few of the most important ones later on in this article.
- Central Processing Unit (CPU) — The “brains” of the SoC. Runs most of the code for the Android OS and most of your apps.
- Graphics Processing Unit (GPU) — Handles graphics-related tasks, such as visualizing an app’s user interface and 2D/3D gaming.
- Image Processing Unit (ISP) — Converts data from the phone’s camera into image and video files.
- Digital Signal Processor (DSP) — Handles more mathematically intensive functions than a CPU. Includes decompressing music files and analyzing gyroscope sensor data.
- Neural Processing Unit (NPU) — Used in high-end smartphones to accelerate machine learning (AI) tasks. These include offline voice recognition and camera object segmentation.
- Video encoder/decoder — Handles the power-efficient conversion of video files and formats.
- Modems — Converts wireless signals into data your phone understands. Components include 4G LTE, 5G, WiFi, and Bluetooth modems.
You may have also heard of something along the lines of a manufacturing process in the context of SoCs. It’s often listed as a number in nanometers (nm). Generally speaking, the smaller the nm size, the smaller the internal components of the SoC. This is better for power efficiency and compactness. That said, there are different methods of manufacturing that can make direct comparisons tricky. At the time of writing, 4nm is the smallest available manufacturing process used for smartphone SoCs.
Examples of an SoC
Now that we have a brief overview of what an SoC is, let’s take a look at a few examples. In the smartphone space, Qualcomm, Samsung Semiconductor, HUAWEI’s HiSilicon, and MediaTek are the four biggest names in the business. Chances are that your smartphone has a chip from one of these companies in it.
Qualcomm is the largest provider of smartphone SoCs, shipping chips for the majority of flagship, mid-tier, and even low-end smartphones each year. Qualcomm’s SoCs fall under the Snapdragon branding. Premium chips boasting the company’s best technology come under the Snapdragon 8 banner, such as the latest Snapdragon 8 Gen 2. Mid and upper-mid-tier products are branded with Snapdragon 600 and 7 series names respectively. For example, the Snapdragon 7 Gen 1 is a relatively new mid-range chip that sports 5G connectivity. Finally, you’ll find entry-level products under the 400 series.
Samsung’s Exynos SoCs operate on a similar premium, mid, and entry-tier scale. These were previously listed as the Exynos 9900, 9800, and 9600 series, with Exynos 7000 series products propping up the budget end of the portfolio. However, Samsung’s latest high-end chip is the Exynos 2200.
Samsung’s Exynos naming scheme used to closely resemble HUAWEI’s, but this has now changed. The Kirin 9000 is HUAWEI’s latest flagship chip, which comes in 4G and 5G variants. The Kirin 600 series is much like the Snapdragon 600 range, offering mid-tier specifications for more affordable smartphones.
Google recently entered the SoC arena too, with the goal of improving AI and machine learning performance for its Pixel series of smartphones. The latest Tensor G2 SoC in the Pixel 7 and 7 Pro enables a slew of exclusive imaging and voice features.
Finally, MediaTek’s Helio range spanned affordable P series products up to the gaming-focused G series. The manufacturer’s latest flagship series is the Dimensity 9200 Plus, followed closely by the Dimensity 8100.
It all starts with the CPU
You might be familiar with the term processor as this is often used interchangeably with the central processing unit (CPU) in this circle of conversation. A CPU is the most commonly used type of processor. It’s designed to be highly flexible and suitable for a wide range of tasks. As such, the CPU runs the Android operating system and your apps. It’s also partly responsible for synchronizing data between other processors inside the SoC.
As a quick overview, CPUs operate using prediction units, registers, and execution units. This is known as the CPU architecture. Registers hold bits of data or pointers to memory, often in 64-bit data formats. Execution units do something with one or more registers, such as reading and writing to memory or performing math. Multiple execution units can be used at once with the CPU, each taking a clock cycle or two to complete their function.
CPUs handle general processing tasks and are quite an important piece of any SoC.
CPUs are flexible enough to suit a wide variety of tasks. Performance can be scaled up and down by changing the clock speed (in GHz), the number of cores, or by changing the underlying architecture to do more with each clock cycle. This latter point is often what’s referred to as building a “wider” or “bigger” CPU, which is how Apple’s phone chips are so powerful. However, there are power and efficiency trade-offs to these wider designs too.
CPUs inside smartphone SoCs come in a variety of flavors, all of which are based on the Arm CPU architecture. The latest CPU cores from Arm are the big Cortex-X3 and Cortex-A715, along with the little Cortex-A510. These three are all based on the latest Armv9 architecture. Smartphone CPUs often appear in eight-core configurations, with big powerful cores for more demanding applications and smaller power-efficient cores to ensure long battery life.
Alongside the CPU, the graphics processing unit (GPU) is another piece of traditional number-crunching hardware packed into a phone SoC. GPUs are far less general-purpose than CPUs and are designed very differently as a result. They are built to repeatedly cycle through mathematical functions in parallel, which they can do much faster than a normal CPU. Remember, there are millions of pixels to fill on your smartphone display, each of which has to be calculated when you’re running an app or your favorite game.
Read more: GPU vs CPU: What’s the difference?
Most graphics operations are repeated over and over again to fill all the pixels on your screen. As such, GPUs are designed to run lots of math all at once on big batches of data. Unlike CPUs that execute one or two operations each cycle, GPUs execute tens, hundreds, and even thousands of parallel operations each cycle. This depends on the size and performance of the GPU design.
The two major GPUs in the Android SoC space are Arm’s Mali and Qualcomm’s Adreno. Both offer bigger and smaller versions of the GPU technology, with flagship chips packing in their most powerful hardware for 3D gaming. Qualcomm doesn’t talk much about the inner workings of Adreno, but we know all about Mali. Apple also has its own GPU for its iPhone SoCs and AMD has entered a partnership with Samsung’s Exynos starting with the Exynos 2200.
Great cameras need good processors
Smartphones are increasingly judged on their photography capabilities. While a high-end sensor and lens hardware are essential, powerful image processing capabilities are an equally important part of the story. The smartphone industry calls this technique computational photography and it primarily relies on the smartphone’s SoC.
While image editing and tweaking are often done on the CPU and GPU, there’s a ton of processing performed on camera sensor data before an image is even saved to your phone. An ISP is a specialized DSP that handles common imaging tasks like Bayer transformations, focusing, demosaicing, sharpening, and noise reduction. In other words, it turns digital information from a camera sensor into a nice-looking picture.
Those last two are particularly important in smartphones, where cheaper handsets tend to oversharpen and produce mushy-looking details.
High-end chipsets are increasingly offering high-end features. For example, Huawei’s Kirin 990 was the first SoC with DSLR-grade block-matching and 3D filtering (BM3D) noise reduction, and Qualcomm and Samsung’s latest ISPs allow for real-time software video bokeh blur.
The bottom line is that great-looking pictures require a powerful image processor.
Next-generation AI processing
Terms like neural processing units, AI processors, or machine learning cores are often used interchangeably but they all tend to mean the same thing inside modern smartphone SoCs: a processor that’s specifically optimized for the mathematics and algorithms commonly used by artificial intelligence (AI) algorithms.
Just like how GPUs are processors optimized for graphics math and ISPs are optimized for image tasks, NPUs are processors specifically designed to run neural networks and machine learning tasks more quickly and efficiently than CPUs. NPUs feature their own local memory caches too, to speed up execution without having to use slower RAM.
Dedicated AI co-processors take the load off the CPU since they're optimized for certain algorithms
Neural networks often require operations that take multiple pieces of input data to generate just a single output. The multiple-accumulate operation is particularly popular, often operating on a variety of data sizes from 16 bits down to 8 and even 4 bits of data. This is very different from the math and data types used by CPUs, although some operations can be accelerated on flexible GPUs.
NPUs are the latest specialized processor to find their way into phone SoCs and enable on-device machine learning. While mostly reserved for flagship-tier chips, this technology is quickly making its way down to more affordable chipsets and handsets already. Google’s Tensor G2 SoC in the Pixel 7 series, for instance, includes the custom Tensor Processing Unit (TPU) that enables exclusive features like instantaneous speech-to-text and a wide variety of camera features.
4G and 5G modems for faster data
The final piece of a modern smartphone SoC is the data modem, which allows you to access data networks from your carrier. Different modems also determine the speed and quality of your data connection. The most powerful modems hit download speeds above 1Gbps. There are also modems for Wi-Fi and Bluetooth data, but we’re focusing on 4G and 5G modems today.
Read more: What is 5G and what does it offer?
In previous years, smartphone SoCs boasted integrated 4G modems. This means that the 4G modem is located inside the SoC. The first 5G modems for smartphones were external, so they had to be connected up to the main SoC. This is less energy efficient but makes it easier to implement high-end features and provides manufacturer flexibility while 5G networks roll out to more consumers.
Integrated 5G modems and capabilities are now here too. Flagship processors from Qualcomm, Samsung, and HUAWEI all feature integrated modems that support both sub-6GHz and mmWave 5G capabilities. The latest flagship 5G phones all feature integrated modems, lending to improved power efficiency when hitting peak data speeds.
More about smartphone SoCs
Phone enthusiasts love to compare CPU and GPU specs, but this is becoming less relevant as performance matures and new capabilities are required. Smartphone SoCs are increasingly less about any single capability and more about a heterogeneous compute approach to solving processing problems. In other words, using the most efficient processor type for the task at hand.
Today’s handsets handle a wider range of workloads than ever before. As a result, the number of dedicated processors inside each chip continues to increase. From basic CPU and GPU components a few years ago to DSPs, advanced ISPs, and NPUs today. These less-talked-about parts are only becoming more important with advances in security, machine learning, and 5G.