Random-access memory, or RAM, is one of the most important components in all devices, from PCs, to smartphones, to games consoles. Without RAM, doing just about anything on any device would be much, much slower. Not having enough for the application or game you’re trying to run can bring things to a crawl or even prevent them from running at all.
But what is RAM exactly? In a nutshell, it’s an extremely fast component that temporarily stores all the information your device needs right now and in the near future. Accessing that information in RAM is insanely fast, unlike slower hard drives which provide longer-term storage.
RAM is essentially your device’s short-term memory. It temporarily stores (remembers) everything that runs on your device, like all the services in Android, your web browser, your image editing tool, or the game you’re playing. You don’t want the CPU digging through your slower storage(ROM), every time you request a new browser tab or load a new enemy to shoot. As fast as storage is compared to drives of years gone by, they’re still far slower than RAM.
Like short-term memory, though, RAM doesn’t remember everything forever. It’s a “volatile” technology, meaning that once it loses power, it forgets everything. That makes it perfect for handling the multitude of high-speed tasks that your system throws at it on a daily basis. But it’s also why we need storage systems like ROM, which actually hold our information when you turn the system off.
It all sounds complicated, and it is, but all you need to understand are three basic things: RAM is a place to hold data for a short period of time, data placed there can be read or written very fast, and data in RAM is erased when you shut your phone down. Additionally, a portion of the RAM in your phone is used as soon as you turn it back on and no apps or even the OS is able to use that portion. This goes for just about any computer; they (almost) all have RAM and they use it the same way.
The most common type of RAM sold today is DDR4, though older systems may use DDR3 or even DDR2. The numbers simply denote the generation of RAM, with each successive generation offering faster speeds through greater bandwidth — a higher megahertz (MHz) rating. Each generation also has physical changes, so they are not interchangeable.
We can see that a phone that's doing more behind the scenes needs more RAM installed. Since almost every phone comes with 6 GB of RAM now, there is no real difference here and a Pixel phone just has a little more memory to have another app or two up and running because it's interface isn't using as much. It's also why Samsung, LG, HTC, and others have included ways to kill running processes for the times it needs a little boost in performance. If you kill all the apps you can, apps that were not already in memory will start a little faster.
The speed of the RAM is known as 'clock speed'. For cell phones the clock speeds of RAM are kept at moderate rates of 300 to 500 MHz to save on power usage.
RAM in smartphones are similar to RAMs in PCs, like DDR3, DDR4. Currently flagship phones are equipped with LPDDR5 or LPDDR4(low power double data rate version 4) RAMs which are capable of transmitting data at 3,200 Mbit/s per pin and consume just 1.1volts.
In a laptop computer faster DDR3 SDRAM (double data rate third generation synchronous dynamic random access memory) are used, but they consume much more power and so cannot be used in smartphones.
