Computers or even smartphones must be able to access and display information within a very short time. That’s what the so-called RAM is for. But what exactly does the term mean and how does the whole thing work? TECHBOOK explains it.
RAM is the short-term memory of a device. Data required for current processes is temporarily stored there. But how does it work exactly?
What exactly is RAM?
The abbreviation RAM stands for Random-Access Memory, which in German means memory with random or direct access. Such direct access storage includes SSDs, USB sticks and also the RAM in a computer, tablet or smartphone. The abbreviation RAM is often used as a synonym for main memory.
Direct access means that data can be accessed and stored on the storage at will. The main memory or RAM plays a special role. It is the central hardware that ultimately determines the system performance and speed of a desktop computer, notebook, smartphone, tablet or smart TV.
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Fast access to data via RAM
RAM temporarily stores data that a computer needs to access as quickly or as frequently as possible because it is needed for ongoing processes. This is where RAM differs from the built-in hard drive, for example, which permanently stores data. Unlike RAM, the hard drive is not erased when the computer is turned off.
A popular example is working with Microsoft Word (or a similar text program). When Word is loaded, the RAM gets the data from the hard drive because texts, images, etc. are stored there. Word functions such as text entry, on the other hand, are carried out in real time because the RAM works much faster than the hard drive due to the data loaded.
This becomes particularly clear when the edited document is saved, which takes a few seconds depending on the computing power. This time would be incurred if the RAM did not store any data and instead accessed the hard drive every time. It would be impossible to work with such a device. The danger, however, lies in the fact that the data is only stored temporarily in RAM. If the computer crashes, the data from the RAM is lost.
That’s what matters
The two most important RAM specifications are capacity and speed. Capacity is measured in gigabytes and indicates the amount of data the RAM can process. The larger the capacity, the more applications can run at the same time. When the RAM is full, applications are accessed directly from the HDD or SSD storage – and this takes significantly longer.
The unit for speed is called megatransfer per second (MT/s). This is the data rate that the RAM can achieve. Manufacturers often still specify the speed in megahertz (MHz) – a holdover from the time when the data rate corresponded to the clock frequency. However, MT/s is now a more precise and comparable measurement of RAM speed.
The higher the rate, the faster the memory can respond to requests. The relationship between capacity and speed should always be balanced. In some cases, it also depends on the intended use of a device. A gaming PC, for example, benefits more from high speed. A work computer on which videos are edited and many processes run in the background primarily needs capacity.
RAM comes in different versions or form factors. Today, a DDR-SDRAM (Double Data Rate Synchronous Dynamic Random-Access Memory) is common, the variants of which differ in speed, capacity and energy consumption – and of course also in price.