Processor
This is the spec you’ll probably see most frequently to denote performance. The processor is really the heart and soul of your phone. Different processors are usually classed by speed, which is expressed in gigahertz, or GHz. Additionally, modern processors are made up of multiple cores, which are individual processing units that can handle separate tasks. Duties can be split among the cores, allowing for parallel computing, and thus, faster output. Processors, specifically for smartphones and other mobile devices, are also termed “system-on-chips” or “chipsets” because they are usually a collection of multiple components on a single integrated circuit, like the device’s radios for calls and data, as well as the graphics processing unit.
Simply put, the faster a processor is and the more cores it has, the faster your phone should be. Here are some more specific descriptions of terms related to processors.
Manufacturers and brands (i.e. Qualcomm, MediaTek, etc.)
There are just a handful of companies that make processors for mobile phones. Qualcomm is the biggest, and they’re responsible for the Snapdragon series. Most devices running Google’s Android operating system feature Snapdragon chipsets, and Qualcomm has broken up its products into four classes: 200, 400, 600, and 800. In Qualcomm’s naming convention, the processors get faster as the numbers get bigger. So if you read that a phone contains a “Snapdragon 835,” you’re looking at Qualcomm’s top-of-the-line processor. Conversely, a “435” is a relatively lower-end chipset.
MediaTek is the second-largest producer of processors in Android phones. Devices running their chipsets are typically more common in Asia, though you can certainly find products in the Americas and Europe containing their hardware. MediaTek’s high-end processors are known as the Helio X series, with the Helio P series slotting just underneath. The rest of its offerings have less remarkable names, beginning with MT67, followed by some more numbers. As you’d expect, the bigger the number, the more powerful the processor — so an MT6753 outclasses the MT6738, for example.
There are other companies that produce processors too, like Huawei with its Kirin brand, as well as giants like Samsung and Apple that produce chipsets exclusively for their own products. Samsung’s processors are dubbed “Exynos,” while Apple has adopted a naming scheme of “A,” followed by a number. Apple’s processors are more generational in nature, so while the same rule of bigger number equals better performance applies, the A10 is also two years newer than the A8. There’s also the “X” series, like the A10X and A9X — though these are reserved for iPads and have yet to appear in a smartphone.
As an example of three high-end phones with relatively similar performance, the Samsung Galaxy S8 uses a Qualcomm Snapdragon 835 in North American models, and Samsung’s own Exynos 8895 internationally. Apple’s iPhone 7 uses the company’s own A10 chip, while the Meizu Pro 6 is one of only a few phones to use MediaTek’s Helio X25.
GPU (Graphics Processing Unit)
Packaged with a mobile processor is a graphics processing unit, or GPU. The GPU is responsible for handling a device’s visual output, particularly where the creation of three-dimensional images is concerned. It usually comes into play with video games and, more recently, augmented reality applications (where the device “augments” the feed coming from its camera with computer-drawn objects and effects).
Because the GPU is packaged within the processor on a smartphone, you won’t find many straight comparisons being made between GPUs in different devices. For example, any phone using a Snapdragon system-on-chip will also employ one of Qualcomm’s Adreno GPUs. Again, the higher number is better, so going back to the Snapdragon 835 as an example, the GPU used is Qualcomm’s Adreno 540. In terms of measuring GPU power, floating point operations per seconds, expressed as GFLOPS, are typically a better indicator of performance.
Memory
Memory on a smartphone spec sheet is expressed in two ways, and they illustrate different aspects of the device. There’s random access memory, or RAM, and read-only memory, or ROM.
RAM (Random Access Memory)
Random access memory refers to memory that is used to store things like active operations and programs. When you load an app, close it, and move to another app, the first app is stored in your device’s RAM. That means that when you return to it, content stays loaded so it can be accessed more quickly. Having more RAM is important for multitasking because it allows you to switch between apps, and have multiple operations going on at the same time even in the background.
Most modern phones comes with at least 2 or 3 gigabytes (GB) of RAM. At the midrange, 3GB is the norm, and high-end phones typically feature at least 4GB — though even that number is quickly rising. It’s important to note that more RAM also doesn’t necessarily mean you will see better performance, for quite a few reasons.
ROM (Read-Only Memory, a.k.a “internal storage” or “flash memory”)
Read-only memory is more commonly referred to as “storage” because it refers to the amount of space you have to store files and media on your device. If you put a song on your phone, download an app, or take a photo, this is where it goes. Most phones today come with at least 16GB of storage, though 32GB is becoming more common as users always need increasingly more space.
Additionally, it’s important to note that you never are given quite the amount of ROM as you’re told, because a portion of it is occupied by the device’s operating system, as well as any subsequent updates. In other words, the amount of storage that you’re unable to use may grow through the life of your phone, which is why users frequently turn to another source for extra space.
MicroSD cards (a.k.a. “external storage” or “memory card”)
Many Android phones feature slots for MicroSD cards, which offer additional storage memory beyond what your device already contains. While apps and media can be stored and moved to the microSD card when necessary, it’s not the default option on most phones — meaning you’ll have to manually send content there, or instruct your phone to save certain media types to external storage whenever possible.
MicroSD cards come in a variety of sizes, and most devices support cards up to 256GB — greatly increasing the amount of content you can keep on your phone. Better yet, they’ve become incredibly inexpensive over the years. With the price of modern MicroSD cards, you can double the storage of a 32GB device for just around $10. Check out our guide on how to use a MicroSD card with your Android phone for more information.
Display
Display technologies are always changing, and there are a number of factors that affect the quality of a phone’s screen. Manufacturers often focus on things like size, resolution, and color representation in marketing. As it’s the very first element of a phone you typically notice or interact with, the display tends to receive a lot of attention.
Resolution (i.e. 1920 x 1080, 720p, QHD, etc.)
Resolution refers to the number of pixels present in a display, and you can think of a pixel as one unit of the screen that is illuminated to compose an image. Modern displays contain millions of pixels, and the number is typically expressed in a “width by height” figure in landscape format, like 1,920 x 1,080. The higher resolution the display is, the more pixels it packs in a given space, and the sharper the image quality will be.
Common resolutions, like 1,280 x 720 or 1,920 x 1,080, are further abbreviated to 720p and 1080p, respectively. The “p” refers to progressive scan, which deals with the manner in which each of the display’s lines of pixels is illuminated. This isn’t something that really concerns smartphones, however, and tends to play more of a role in televisions and computer monitors.
You’ll often see 720p referred to as “high-definition,” (HD) and 1,080p called “full high-definition” (FHD). A few years ago, 1,080p was pretty much the highest resolution on a phone, but more recently some high-end devices have released sporting “quad high-definition” (QHD) panels, with a resolution of 2,160 x 1,440. They’re called “quad” because they feature four times the number of pixels found in a 720p display.
At the top of the food chain is 4K, or 3,840 x 2,160 specifically — there’s only a few phones at the moment that features such a high-resolution display, such as Sony’s Xperia XZ Premium. Other flagship phones, like the Galaxy S8 and LG G6, tend to fall somewhere in the QHD range — though other recent advancements in display design have complicated things even further.
Aspect ratio (i.e. 16:9, 18:9)
Aspect ratio refers to the relationship between the width and height of a screen. For a very long time, phones adopted the same aspect ratio as high-definition televisions: 16:9. However, the past year has seen an industry-wide push toward wider formats, like 18:9. The aforementioned Galaxy S8 and LG G6 both feature screens that are roughly 18:9. If you’re wondering why they simply don’t call it 2:1, it’s down to marketing — 18:9 sounds larger, or so the thinking goes.
The Galaxy S8 specifically has a resolution of 2,960 x 1,440 — so it’s actually a little bigger than the QHD standard, where the screen would only be 2,160 pixels wide. The aspect ratio for Samsung’s phone is technically 18.5:9.
Display Size and pixel density (PPI)
The size of a screen is measured diagonally, from opposite corners. While resolution and physical size are important factors in determining screen visibility and clarity, they don’t tell you much on their own. For example, a small display at a given resolution will look sharper than a larger display at the same resolution, simply because the same number of pixels are packed into a smaller space.
This is what the term “pixel density” is all about, and you’ll typically see manufacturers refer to density in “pixels-per-inch,” or PPI. This is a great measure that is perhaps even more telling than simply resolution alone, because it takes account of the device’s display size as well. It’s particularly useful in sizing up compact phones: a 5.5-inch display would look pretty poor at just 720p, but the same resolution just an inch smaller will deliver a much more satisfactory visual experience.
Ever heard Apple refer to their products as having “Retina displays?” While the term is fully marketing on Apple’s part, it is based on pixel density and the idea that the human eye is unable to distinguish between individual pixels past a certain PPI at a given range. Apple has said for many years that the threshold is 300 PPI, if you’re holding a phone about 10 inches from your face. There’s debate as to whether that distance is a good real-world average.
Display technologies (LCD and OLED)
Resolution and aspect ratio don’t tell the whole story, because there are a variety of technologies at manufacturers’ disposal in building displays. The two most common are Liquid Crystal Display (LCD) and Organic Light Emitting Diode (OLED).
Though there are a variety of technical differences between the two methods, the main difference concerns the way pixels are lit in each application. LCD panels utilize one backlight for the entire screen. That means that even when the image shown is intended to be pitch black, the backlight is still active, and some light will shine through.
Conversely, OLED displays use an organic material that powers pixels individually. As a result, pixels can be turned completely on or off — and when they’re off, they can deliver true black, with zero light emitted. That benefits battery life, because much less of the screen has to be powered when images are particularly dark. It’s for this reason you’ll see many OLED phones with special features like Moto Display, where the screen will deliver notifications through white text on a black background while the phone is locked, without any adverse effects on battery life.
Given that key difference, you might think OLED is unquestionably better than LCD, but it struggles in a few key areas. For one, less light passing through the screen means less overall brightness. There have also been reports of a higher likelihood of burn-in and faster degradation over time, but the main downside is that OLED panels are still difficult and expensive to produce. Major strides have been made in the last decade, however, closing the cost gap and chipping away at some of LCD’s advantages, and over time increasingly more manufacturers have moved to OLED to power their displays.
Another term you’ll often see in relation to LCD displays is in-plane switching, or IPS. There are several different types of ways in which LCD screens can be built, but when it comes to mobile devices, IPS is by far the most popular because of its strong viewing angles and color reproduction. Another technology, Twisted Neumatic (TN), predates IPS and was used more frequently in early LCD panels because it was cheaper to produce. However, these days even the least expensive smartphones utilize IPS screens.
Battery
Battery size is measured in milliamp hours (mAh). The higher the mAh, the greater the capacity, and the longer your phone should last on a charge — though other factors, like the power efficiency of your phone’s operating system and software, the display type, and amount of usage have a massive impact on battery life. As applications have become more demanding and screens have gotten sharper and better, they’ve also consumed more power, forcing phone makers to stuff bigger batteries into their devices.
For this reason, there’s a great deal of variation between smartphones when it comes to battery size. As a mark of how far we’ve come, the original iPhone featured a 1400mAh battery back in 2007, whereas the iPhone 7 Plus packs a battery over twice as large, rated at 2,900mAh. Other phones specifically designed for long life have even larger batteries, like Lenovo’s newly-released Moto E4 Plus with its 5,000mAh battery.
Fast-charging technologies (i.e. Qualcomm Quick Charge)
For a long time, the unfortunate side effect of bigger batteries was that they’d take longer to charge. However, many smartphones on the market today can safely handle receiving greater amounts of power at once, thanks to fast charging technologies like Qualcomm’s Quick Charge specification. Through the use of a specialized Quick Charge adapter, you can top up these phones more rapidly than you would with a typical charger.
For example, Qualcomm said that Quick Charge 4 — the latest iteration of the technology — can deliver five hours of battery life, on average, in five minutes of charging.
Wireless Charging (Qi and PMA)
Wireless charging has existed for a while, though it’s struggled to gain a footing in the majority of phones on the market. There are two standards in the industry for delivering power wirelessly: Qi and PMA. Once upon a time, you’d have to choose a charging pad and phone built on the same standard to match, however most phones today that support wireless charging work on both. There’s no discernible difference in the way either operates.
A wireless charger uses an induction coil to generate an electromagnetic field, while another coil in the device converts that energy to electrical current. The technology that exists can only pass through a small amount of space, and is highly dependent on the coils being as closely aligned as possible. For this reason, many charging pads and phones utilize magnetic pins to ensure transmission. If the base and the device are even millimeters off, charging won’t occur.
Another disadvantage is that wireless charging isn’t always the most efficient method to top up your phone, and is typically slower even when a “fast” wireless charging pad is used. Furthermore, the differences between the speedier protocols manufacturers employ can complicate things. For example, Samsung makes its own fast charging pads specifically for its devices, though those same phones aren’t guaranteed to work with similar pads sold by other companies.
If you’re interested in wireless charging but your phone doesn’t support it out of the box, you may be able to buy a case for it that will give it the capability. You can also check out our handy guide to find out about the best wireless charging pads on the market.
Camera
While manufacturers frequently tout megapixels in their marketing, there is a plethora of factors that impact camera performance. Cameras are, of course, already complicated pieces of tech in their own right, so in this section we’ll focus on some of the terms most closely associated with smartphone photography.
Megapixels (MP)
Camera resolution is expressed in megapixels, and a single megapixel refers to one million pixels. So, if a camera captures a 12-megapixel image, you’re looking at 12 million pixels at a width of 4,000 by a height of 3,000 (though those figures may vary depending on the aspect ratio you’re shooting at). Like display resolution, the resolution of your camera will dictate sharpness and detail. However, it doesn’t affect color saturation or low-light performance, nor does it affect aperture — all of which also significantly impact the way your photos will look.
Aperture (f/)
The aperture refers to the size of the opening that controls the amount of light that reaches the lens. Aperture is expressed in f-stop values, like f/1.8 and f/2.2. The smaller the number, the larger the opening, and the more light you’re letting into the shot.
Here’s the thing though: While a proper digital camera will let you manipulate aperture, most smartphones aren’t equipped for it. As a result, the cameras in the wide majority of phones have fixed apertures. This not only impacts your ability to adjust lighting on the fly, but how the entire scene is captured as well. Lower f-stops create a shallower depth-of-field, which blurs the background of your images while leaving the focus of the shot crisp and clear. They’re also particularly helpful in low-light situations, a weakness of mobile photography.
The aperture value in most flagship phones has fallen over time, with the Galaxy S8 sporting an f/1.7 lens, the iPhone 7 coming in at f/1.8, and the Google Pixel at f/2. The general consensus is that all of these devices have excellent cameras, and a part of that is down to the larger aperture, as well as image processing.
Pixel Size (µm)
Each pixel captured in an image refers to a photodetector site on the camera’s image sensor, and when these sites are physically larger, they absorb more light. This is the reasoning behind HTC’s UltraPixel technology, for example — larger “pixels” that capture more light, and therefore perform better in situations where light is scarce.
Pixel size is expressed in microns (µm), and some phones that really prioritize camera performance will list this information in addition to megapixels and aperture. The Galaxy S8 features 1.4µm pixels, for example, while the Google Pixel’s are a bit larger, at 1.55µm.
High Dynamic Range (HDR)
High Dynamic Range (HDR) is a photography technique that has found its way into many modern phones’ cameras over the last several years. With HDR activated, your phone will actually take multiple shots when you press the shutter button — usually three. Each of these photos will be taken at a different exposure, so you’ll typically have an underexposed photo that’s very dark, an overexposed photo that’s too bright, and another somewhere in the middle.
The phone will then generate a composite based on each of these exposures, pulling different parts of each one to create a final image that is ideally more balanced than an ordinary photo. The parts that would normally be lost to total darkness are brighter and thus more visible, because they were sourced from the overexposed image. The other sections that would normally be far too bright would be toned down a bit and contain more color, because they were sourced from the underexposed image.
Sometimes HDR is very effective, and sometimes it creates an over-saturated or washed-out mess. Every phone, just like every photo op, is different, so your results will vary. Fortunately, many phones save a standard copy of an image alongside an HDR one, so you can choose the best example in every circumstance.
Dual Cameras
Dual cameras are a growing trend in the industry, though each device handles the use of multiple cameras differently. Many phones employ additional software and image processing tricks in tandem with a second lens to enable some pretty nifty special features.
For example, the iPhone 7 Plus pairs its normal lens with a telephoto lens, which features a narrower field of view. Through the use of this second lens, the iPhone can achieve 2x optical zoom — an unusual feat for a phone, as most handsets can only manage digital zoom. It can also use the telephoto lens to create a shallow depth-of-field effect for portrait photos, where the background is blurred.
The LG G6 is another example of a device that uses its second lens in a unique way, that operates in a totally different fashion from the iPhone 7 Plus. Unlike Apple’s scheme, the second lens on LG’s device is actually even wider-angled than the standard lens. This makes it ideal for expansive landscapes and group shots.
Other Terms
USB-C, Micro USB, and Lightning
These are the three types of connector ports you’ll find on modern phones, that are used for everything from charging to listening to music. USB-C (or Type-C) is the newest standard, appearing on most current Android devices. USB-C is reversible, meaning it can be plugged in through either orientation, and it also has the ability to deliver power and data faster than its predecessor, Micro USB. Lightning, on the other hand, is Apple’s proprietary connector, only used in the company’s own mobile devices. It is also reversible, though it’s important to note that none of these connectors are interchangeable.
Bluetooth
Bluetooth is a protocol for wireless data transmission intended for short range uses. Just about every modern phone features Bluetooth, and the platform is often used for wireless communication between a device and a paired accessory, like a pair of wireless headphones, speaker, or smartwatch. Bluetooth 5 is the latest version of the technology.
Data (LTE and Wi-Fi)
LTE stands for “Long Term Evolution” and is the leading wireless standard by which phones transmit and receive data. Mobile carriers operate LTE networks, and these networks allow your device to connect to the internet. LTE replaced several other technologies, such as HSPA+ (now commonly referred to as 4G) and 3G years ago, and 5G is reportedly the industry’s next step.
Data speeds are measured in megabits per second, or Mbps, and LTE typically averages about 13 Mbps for users in the United States, according to recent estimates. Additionally, many users employ a Wi-Fi network in their home or office, which allows for the use of a local connection — rather than a mobile network’s towers — to connect to the internet.
If you have other wireless devices, like a laptop or smart TV, you probably do this already. However, many wireless providers meter your LTE data — and once you hit your monthly cap, you could be throttled or charged with overage fees. As such, it can be helpful to use Wi-Fi whenever possible, to avoid eating away at the data limits imposed by your carrier.
Smartphones in the U.S. are also sold as either GSM, CDMA, or unlocked. GSM means you can use it on AT&T and T-Mobile, whereas CDMA devices will only work on Verizon and Sprint. GSM is far more popular globally, and it’s why you should always think about buying an unlocked phone, so you’re not tied to a certain standard. You can read more about LTE, and smartphone bands here.
NFC (Near Field Communication)
NFC, or Near Field Communication, is yet another wireless technology, though it works through physical contact or extremely short distances. For this reason, NFC has become a popular protocol for mobile payments. With an NFC-enabled smartphone and a digital wallet app like Apple Pay or Android Pay, you can save your credit or debit card to your phone and complete a transaction by tapping your device to the payment terminal. Many phones also support NFC as a method of transferring small amounts of data quickly between devices, like photos.
Water Resistance (IPXX)
More and more phones these days feature water resistance — the ability to withstand splashes or submersion, usually at a given depth up to a maximum amount of time. These capabilities are expressed in something called an IP rating, which refers to the industry-wide “International Protection” standard.
IP ratings include numbers, like IP67 or IP68, that denote the strength of the device’s water resistance. The first number represents protection against dust, dirt, and sand, while the second is the one actually concerned with water. An IP67-rated device should be able to withstand submersion up to 1 meter deep for a maximum time of 30 minutes. An IP68-rated device, on the other hand, can survive for the same amount of time in 1.5 meters of water. The iPhone 7 sports an IP67 certification, while the Galaxy S8 fares a bit better, at IP68. Visit our guide to find out the best waterproof phones on the market now.
If there are any terms you’d like to explore in greater detail, check out one of our handy guides, or ask away in the comments.
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