Smartphone processors

Devashish
4 min readDec 27, 2020

Buying smartphones always brings the performance question, Is the processor best suited for my day-to-day needs? when we see specifications that says something like,

“Snapdragon 626 octa-core processor with ARM Cortex A53 4*2.2Ghz & 4*1.8GHz based on 14nm process”.

Okay…. , this is a lot to digest 😒, Let’s break this into pieces and understand what is cortex A53 means? what does this 14nm signify? what is this 2.2GHz denotes? we’ll discuss this all, so without waiting any further, let’s dig deep into it.

First thing first why the processor is important,
A Mobile processor, also known as SoC (System on Chip), is a component that controls everything going on, in your smartphone device and ensures it functions correctly. cool, let’s see what is this Snapdragon thing? It is just the brand name of Qualcomm’s mobile processors. there are other popular processor brands available in the market like Mediatek ( Helio, Dimensity), Samsung (Exynos), Hisilicon by Huawei (Kirin), Apple(A Bionic), and Spreadtrum(UniSoc, Tiger). we have some other brands which develop mobile processors but they are not really that popular like Nvidia (Tegra), Intel (Atom)

Okay, let’s understand the cores, A core is the individual processing units, A processor is divided into different processing units to provide better multitasking and performance. It is better to have multiple cores but practically it is not always necessary more cores mean better performance. This all depends on what is that task a core will perform and how powerful the individual cores are, the performance of the core depends on its design, architecture, and efficiency.

Okay now here we came to the design part, we’ll go with the above example “octa-core processor based on ARM Cortex A53, 4*2.2GHz & 4*1.8GHz” okay so what is ARM here 💪🤔 no no.. not that… it is “Advanced RISC machine” or “Acorn RISC Machine” company. they design and develop the architecture of the processor, in the above example Cortex A53 is one of the Architecture based on which the cores of processors are designed. ARM provides licenses for these designs to different processor manufacturers. There are two levels of license: core license & architectural license.
Core license allows the manufacturer to take a full core design and incorporate it into an SoC along with a GPU, memory controller, etc. With the architectural license, the manufacturer can design its own ARM architecture cores with any configuration, it desires as long as the core design is compatible with the ARM instruction set, for example, snapdragon kryo cores, Apple custom cores, etc.

Okay now let’s understand the clock speed, semiconductor processors have millions and billions of transistors integrated into the circuit. To execute the instructions, these transistors switch their bits ( states 0/1 ) very fast at a particular rate, this rate is called its clock speed, the faster switching of bits makes the performance better. there’s a thing to keep in mind, faster clock speed brings more power consumption as well. this clock-speed we measure in Hertz. the number of switching of bits in a second is said 1Hz.

In the example, we see an octa-core processor all of them are based on Cortex A53 architecture, in which 4 Cores are clocked on 2.2GHz, are high-performance cores because of higher clock speed it gets better performance then next 4 cores are based on 1.8GHz, are power-efficient cores as they operate on lower clock speed and uses less power.

So far so good, but we have seen something ’14nm’ term in the example, What was that?
Okay, So we know that processor cores are fabricated of a massive number of transistors and these transistors are fabricated on a small silicon wafer plate, this nm term is said node-process, tells about the closed packing of transistors on the silicon wafer, more specifically the gate size of transistors through which electrons flow. close-packing or smaller node-process improves efficiency and reduces power consumption because electrons flow will be of sort distance and It will consume lesser power.

But Nowadays this nm node-process became a sort of marketing gimmick, Every manufacturer has their own method of calculating this, after the introduction of FinFET transistors, so it’s better to check transistor density, number of transistors per mm² to understand the packing and power efficiency of the processor.

Thanks for your time,
If you see something incorrect / misinformation or have any doubt, please comment down below.

--

--