Smartphones are an amazing piece of electronic equipment. There is just so much you can do with them, from calling to browsing the internet, and taking photos to using it as a mobile hotspot. And they just keep getting better and better.
Obviously, to keep up with the increasing demands of today’s mobile-addicted users, smartphones need some serious power under the hood in order to perform well. The central processing unit (CPU), also known as the processor, is the driving force of any smartphone and is responsible for how fast a smartphone can run.
If you look up smartphone specifications, you’ll notice that oftentimes it mentions the number of cores a CPU has. This is an important number because the more cores a CPU has, the better it will perform.
The question is…
What is a smartphone CPU core?
A smartphone chipset with an 8-core CPU comprised of four big cores and four little cores.
A smartphone CPU core is an individual processing unit found on the central processing unit (CPU) of a mobile phone. It is responsible for receiving and executing instructions that are sent from the user to the phone.
For example, when you launch your favourite app on your phone, there are many instructions and tasks being carried out by your phone in order to launch the app and have it respond to your input on the screen.
The core is responsible for making sure that all the tasks and instructions are carried out correctly and as quickly as possible. The speed at which the CPU core can execute instructions (also known as the clock speed) is measured in cycles per second and expressed in gigahertz (GHz). The higher the clock speed, the faster the core. So, a 2.4GHz CPU core is faster than a 1.8GHz CPU core.
Components of a core
A mobile phone CPU core has several sub-components. Most of these sub-components are grouped together and collectively function as the core.
Below are the CPU sub-components that make up the processing core.
Arithmetic Logic Unit
The Arithmetic Logic Unit (ALU) is a very fundamental part of the entire processing unit. As the name suggests, this unit is responsible for all the basic arithmetic and logic operations of the core.
Examples of these are addition, subtraction, multiplication, and division. The ALU is also responsible for comparisons. It can compare numbers, letters, and special characters.
The design of the ALU determines how powerful the CPU will be. However, the more complex the ALU, the more power it consumes, not to mention the increased heat it will dispel. And even though it might make the CPU faster, it’ll also make it more expensive.
Floating Point Unit
While the Arithmetic Logic Unit is responsible for doing simple calculations, its main focus is on integers (numbers with no decimal points). The Floating Point Unit, or FPU, on the other hand, does the same calculations but for floating-point (numbers with decimal points) calculations.
Because of space, power, and price saving reasons, not all smartphone processor cores have FPUs, particularly on the cheap end of the spectrum. Although a processor can function without an FPU, having one provides a faster way of handling non-integer numbers.
Registers
A register is a very fast type of local memory that is responsible for executing program instructions. Whatever the processor is working on, it gets the instructions immediately from the registers. They are storage spaces that provide the CPU with instructions very quickly.
In computer architecture, there is a memory hierarchy that places computer storage in a hierarchical pyramid based on how quick the response time is. Registers are at the top of the pyramid because of fast they are.
A register is a very quick and easily accessible location for the processor to access instructions, which makes for fast processing speeds. They are normally measured by the number of bits they can hold, for example, a “32-bit register”.
Cache
Cache (pronounced “cash”) is temporary fast storage that is just below registers on the smartphone memory hierarchy. While registers store instructions that are immediately required by the processor, cache memory stores data that the processor is likely to require but is not currently processing.
The main aim of cache memory is to improve processing time. Instead of having to search for data in the main memory (RAM), which takes time, the cache provides a shortcut by storing the data that might be required.
Control Unit
A control unit is a component within the processor core that controls the operations of the processor. It relays information to the ALU, the memory units, as well as input and output devices. This information lets all the relevant units know how to respond to instructions.
The smartphone processor control unit receives input information from the user, which it converts into a control signal that it forwards to the CPU. The smartphone’s processor then tells the attached hardware what to do.
For example, when you increase the volume on your mobile phone, the control unit will take that instruction from you and tell the processor what needs to be done. The processor will then instruct the output device (the speakers) to be louder.
Not only that, the control unit will tell the processor that the display needs to light up and show the graphic of the volume going up on the screen. The processor then forwards the instructions to the relevant hardware.
Multi-core processors
In the past, smartphones had one CPU that carried out all the instructions sent to it. As time went by and smartphones became more and more sophisticated, it became necessary to find a way to increase the speed at which the CPU can perform without overheating the device. Thus, multi-core processors were born.
As the name suggests, a multi-core processor is a CPU that is made up of more than one processor core combined into a central processing unit. It’s basically a CPU that’s made up of multiple CPUs called cores.
Each core on a smartphone CPU is able to able to carry out instructions independently of the other core(s) to execute simple instructions such as texting. If a task is particularly demanding, as is the case with mobile gaming and video editing on your phone, then multiple cores work together to complete the task quickly and smoothly.
Having multiple processors (cores) is essentially what makes it possible for a smartphone to multitask. They’re all attached so that they can communicate easily and much quicker. Multiple cores also help to keep the CPU cool.
The number of cores on a mobile CPU depends on the manufacturer and the model of the chip. When looking at the specs of a phone, it is often easy to tell how many cores a phone’s CPU has by looking at the name.
Dual-core= 2 cores
Quad-core= 4 cores
Hexa-core= 6 cores
Octa-core= 8 cores
big.LITTLE
A large majority of smartphones have processors that use the ARM architecture. In order to maximize battery power and use it efficiently, ARM (a company that develops mobile phone chipsets) developed a processor chip that has two quad-core processors that it calls “big.LITTLE”.
The purpose of the big.LITTLE design for CPUs is to maximize efficiency and minimize power consumption. This is achieved by paring a group of small cores with a group of large cores, hence the name ‘big.LITTLE’.
The little cores take care of the day-to-day low-intensity functions of the phone while the big cores (which are only activated when needed) take care of the more intense phone activities such as mobile videography, photo editing, gaming, etc.
To create buzz and sell more units, smartphone companies often market their processors as being 8-core. While this is true in theory (four little cores plus four big cores), in most cases, a maximum of four cores work at a time. Therefore, it is not as easy to find a phone that is truly 8-core and uses all eight of them at the same time.
Do more cores mean a faster CPU?
Contrary to popular belief among those with little knowledge of the subject matter, doubling the number of cores on a CPU does not necessarily mean that the phone will be twice as fast under the same usage scenarios.
Yes, having more cores does help increase the speed and performance of a smartphone but only to a point. The more cores on a CPU, the more raw processing power it has. But there are other factors that contribute to the speed of a smartphone apart from the number of cores.
For example, if your phone has a dual-core CPU with two 1.8GHz cores, it does not mean that the phone’s CPU will have a combined speed of 2.6GHz. It means that each core can run at 1.8GHz when performing individual tasks at the same time.
How many cores are enough for a smartphone processor?
Smartphone operating systems and a large number of smartphone apps are commonly designed to operate across four cores. This has led many to conclude that smartphone CPUs need no more than four cores.
And although that is a valid point, there are some benefits to the theory behind having more than four cores, even if they don’t all work at the same time.
Conclusion
A smartphone CPU core is a very important part of a smartphone’s internal architecture. On its own, it can perform calculations and execute everyday tasks on the phone. But combined with other cores, it becomes part of a larger central processing unit that can help make the phone run faster.
If you’re looking to buy a new smartphone that can run fast, it’s definitely worth looking at the number of cores the phone has. A lot of phones on the high end these days tend to have eight cores. Cheaper phones, however, tend to have fewer cores to keep the cost down.
But remember, there are other factors besides the number of cores a CPU has that determine the overall performance of a smartphone. You can check them out here.
