Introduction to Smartphone SoCs 2 (CPU cores)

Hi, welcome to the second part of our series, Introduction to Smartphone SoCs 2 (CPU cores). So in our last talk, I listed all the major parts of an SoC and I shed light on them. This time, we’re going to look at a major part of the SoC. This is the part that we call CPU cores.


So like I explained in the last talk, I likened your phone to a house and your SoC to a power generator. I also said that the type of generator you have determines the kind of appliances that you can operate.

If you have a big generator, you can pump water, use a pressing iron, have multiple TVs on at the same time and in some cases, a small fridge. A small generator can not do many of these things.

It would be utter foolishness to buy a small tiger generator and complain that it cannot power up your water pump or a pressing iron. Yet a lot of people do these and complain about their phones.

Why? Because they lack a demonstrable knowledge of these matters and (some) actually take pride in their ignorance.

Introduction to Smartphone SoCs 2 (CPU cores)

The System on a Chip (SoC) is a system of CPUs on one chip. Each designed to carry out a specific group of functions but they all work together as a single unit.

The major part of the SoC that helps facilitate this are a group of CPUs that we call CPU cores. The CPU cores are the major computing hub of any SoC. CPU cores are important because they are multi-purpose CPUs that do the major work on any phone.

Other CPUs on the SoC such as the GPU or ISP have very specific functions such as graphics processing or image processing. They only perform these functions.

The CPU cores on the other hand can do everything. The Operating System runs on the CPU cores. The CPU cores have to process apps, games, system functions, background tasks, loading pictures and videos before sharing the graphics load etc.

The importance of the CPU cores cannot be overemphasized. If the CPU cores aren’t powerful, the phone will be unable to process heavy loads. It will not be able to play high definition mobile or emulated games. Videos may take forever to even load and process, and may not even play well. System functions will stop and start for no reason etc.

At least by now, some of us may be seeing how important the CPU cores are. Now that we know about CPU cores, let’s look at who makes them.


Nearly all CPU cores in action today are derived from a single source. A company known as ARM holdings. ARM holdings are currently owned by Softbank.

Before ARM came, the smallest CPUs we had were those microprocessors from Intel which powered PCs at the time. The scientists and engineers who saw the future started trying to shrink computers that would fit into the palm of the human hand.

ARM succeeded and their designs were very small and cool, didn’t need a cooling fan and could carry out reasonable tasks. They kept improving their designs from the 1980s till now, getting better with each generation.

Now I’m going to clear up a very common misconception. ARM doesn’t make CPU cores. I have already made a video about this.

How SoCs are made

ARM does not make CPU cores. What ARM does is that they make the designs. Think of ARM as a building architect. Building architects make designs for buildings which they then sell to home owners who want to build their houses. The Architect may then oversee the building of the house, keyword being oversee, but will not mould a single brick.

Companies that make SoCs

The same thing is what ARM does. ARM makes CPU designs on paper and then sell these designs to the companies that make SoCs.

Smartphone SoC brands explained

These include:

Unlike many architects that simply sell off their designs, ARM keeps hold of the ownership of their CPU designs. So therefore all CPU designs belong to ARM.

ARM markets their designs using two methods:

  1. IP license
  2. Architecture license

IP license

With an IP license, the buyer has no right to make any alterations or adjustment to the CPU design. They just manufacture it the way ARM designed it.

Companies that use ARM’s IP license are MediaTek, Huawei, Google, Unisoc and Samsung.

Architecture license

With an architecture license, the buyer has the right to modify or make adjustments to the design. They can then manufacture the CPU to their own specifications and satisfaction.

Companies that use an Architecture license are Apple and Qualcomm.

IP cores vs Custom cores

IP cores

Cores that are made using an IP license are known as IP cores. They are usually named as ARM Cortex A or X(number) e.g. ARM Cortex A75 or ARM Cortex X2.

Custom cores

Cores that are made using an architecture license are known as custom cores. They’re named by company that customized them.

Apple’s custom cores include: firestorm, icestorm, twister, typhoon, swift etc.

Qualcomm’s custom cores are known simply as Kryo gold and Kryo silver.

Read: What are Qualcomm’s Kryo CPU cores?

CPU power

This is where we now get to CPU power. How can you be able to know which CPU is more powerful than the other?

Thankfully ARM has a very straightforward naming process that can help you instantly tell which CPUs are better and which ones are weaker.

Every ten years or so, ARM updates their CPU designs. Each design period is called a generation. The CPUs of the newer generation are always more powerful than those of the older generation.

ARMv7 generation

This was the CPU generation that was around over 10 years ago. They are:

  • Cortex A5
  • Cortex A7
  • Cortex A8
  • Cortex A9
  • Cortex A12
  • Cortex A15
  • Cortex A17

These CPUs are now very useless today. They’ll be completely unable to handle even what we consider very light tasks.

ARMv8 generation

This was the CPU generation that was around during the last 10 years. They are:

  • Cortex A53
  • Cortex A55
  • Cortex A72
  • Cortex A73
  • Cortex A75
  • Cortex A76
  • Cortex A77
  • Cortex A78
  • Cortex X1

These are the CPUs that are on every CPU in use today with the exception of the flagships.

These are the ones that many users are familiar with. The higher the number, the better the CPU. A78 is better than A75, A72 is better than A55, A55 is better than A53. Easy as that.

An SoC with A76 CPU cores would be considered moderately powerful and any SoC with A78 CPU cores would be considered really powerful. An SoC with A53 cores would be considered weak and an SoC with A7 cores would be considered very weak.

Read: What is ARMv9?

ARMv9 generation

The current generation that we’re in right now. There are currently a good number of ARMv9 CPU cores:

  • Cortex A510
  • Cortex A520
  • Cortex A710
  • Cortex A715
  • Cortex A720
  • Cortex X2
  • Cortex X3
  • Cortex X4

The CPUs of the 8th generation are better than those of the 7th, while the CPUs of the 9th generation are better than those of the 8th generation.

This has already been quite lengthy so I’m am going to give it a rest. That’s the end of this Introduction to Smartphone SoCs 2 (CPU cores) post. I’ll be around to respond to comments, corrections, contributions etc.

Thank you for reading to the end. As always, ensure to check out our links for more information and…