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What’s inside your smartphone?

Smartphones. They’ve become focal points of our lives and connected homes, acting as our games consoles, movie and music players, mobile offices, Wi-Fi hot spots, daily planners and of course, mobile phones. But what’s inside one? 

At a base level, all phones come loaded with a CPU or central processing unit. They also pack radios, a screen, as well as a battery, ports and buttons. Progressing from feature phones and towards smartphones and you can expect to find things like cameras, sensors and pretty hefty amounts of storage, as well as RAM.


CPU (Central Processing Unit)

Starting at the top, the CPU can be likened to the human brain of your phone. It powers things along and its capacity limits how hard you can push your phone’s capabilities. Naturally, more powerful phones will be better for 3D gaming and HD video, whereas even lower-end phones should support standard definition video playback and games like Angry Birds.

CPU power is measured in MHz and GHz – with 1000MHz equalling 1GHz. CPUs are available in single-core, dual-core and quad-core varieties, the more cores and GHz, the more powerful the CPU. More cores won’t always be right for you though, many phones offer less powerful CPUs in order to save power and quad-core phones are  more expensive.

What CPU your phone needs will heavily depend on the operating system it uses. iOS and Windows Phone are more efficient than Google’s Android for example, so can get away with less cores and GHz.

Today, the quad-core CPUs on offer are Samsung’s Exynos 400 quad found on the Samsung Galaxy S3, Huawei’s K3V2 on the Huawei Ascend D Quad and Nvidia’s Tegra 3 chip found on the HTC One X European version. Qualcomm makes the dual-core CPU of choice for Androids, the Snapdragon S4, offering great performance and battery life, as found in the North American Version HTC One X. The iPhone 4S uses a dual-core A5 designed by Apple.

RAM (Random Access Memory)

RAM is short for Random Access Memory, this is different to the memory for storing pictures and MP3s, which we’ll cover later. RAM is used to temporarily store app and program information and carries out the ‘physical’ running of processes, things like playing music, running the web browser or loading a game. RAM is measured in MB, so the more RAM a phone has, the faster it will generally feel and better it will multi-task.


A phone’s Radio sends and receives data, be it voice, 3G, 4G, Wi-Fi or Bluetooth. A cellular radio can be integrated into the CPU chipset as is the case with the Qualcomm Snapdragon S4, or integrated separately as with Nvidia’s Tegra 3 processor.


We interact more with our screen than any other part of our smartphone today. When describing a screen, we usually refer to its size, resolution and type.

Screen size is determined by measuring the distance from bottom left corner to top right corner (or vice versa), and is usually measured in inches. iPhones have historically been 3.5-inches, though the iPhone 5 will probably change this, however the trend for bigger screens has meant Android phones have grown as large as 5.3-inches in the Samsung Galaxy Note.

Screen sharpness is dictated by resolution. This refers to the number of dots, or pixels that emit light and make up your display. The more dots on the screen, the more seamless the image, with Apple coining the term Retina Display to signify a screen with no discernible pixels.

Screen technology on smartphones comes in the form of either LCD or AMOLED. LCDs tend to produce purer whites, sharper pictures and better viewing angles at their higher end, however AMOLEDs offer more vibrant colours and deeper blacks, ideal for dark user interfaces and movies.


Coupled with its processor and software, the battery dictates how long your handset will last. Battery power is measured in mAh, however mAh aren’t everything. Phones lose energy in the form of heat emitted from the phone, radios trying to access a connection and most of all, screen brightness. In fact, the processor has just as much bearing on battery as the mAh capacity. This is nicely illustrated by Qualcomm in the following video which highlights the heat difference across processors.


Cameras are becoming a staple of modern day smartphones. More and more phones are including a front facing camera for video chatting, and most have a camera round the back. The latter camera is always the better performer of the two and some phones such as the Nokia 808 PureView, rivals high-end compact cameras in terms of image quality and shooting options.

Camera resolution is measured in megapixels, with most phones today being 3-megapixels or higher. More important than pixels however is auto-focus, lens and sensor quality. If your camera has autofocus, you can take a variety of shots, including landscape or close-up. Lens quality discerns the clarity of the shot while the phone’s camera sensor dictates graininess and overall quality.


Sensors as the name suggests, sense. They sense light levels, they detect movement and proximity. Why? A light sensor will adjust brightness to save battery, a motion sensor will silence a ringing phone when it’s turned upside down and a proximity sensor will turn off the screen when you put it to your face, so on-screen buttons aren’t pressed mid-call.


We’ve talked about pixels, GHz and mAh, now it’s time to introduce MB and GB. Most phones come with some internal storage, measured in GB. One GB is a thousand MB. Some phones also offer the option to expand the amount of storage you have by inserting a memory card, usually microSD, allowing for up to an additional 32GB of memory.

To give you an idea of storage and its real-world benefits, 1GB will store roughly 2 standard definition movies, 200 songs or 2000 good quality pictures.

There you have it, an introductory crash course as to what’s inside your smartphone. Hopefully you have a better understanding of what to look out for when bagging your next mobile. If you want to know more about any specific element or phone, check out our other guides and reviews.


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