RAM (Random Access Memory)

The term ‘random access memory’ (short: RAM) often pops up when pur­chas­ing a computer, tablet or smart­phone. Even with the latest gen­er­a­tion of smart TVs, the amount of RAM is an important factor that plays into the device’s overall per­form­ance. Because whether you’re streaming movies, surfing the internet, or writing emails – every activity requires the device to load data that is tem­por­ar­ily stored. To make sure that the com­mu­nic­a­tion between in­di­vidu­al com­pon­ents is quick, computer man­u­fac­tur­ers use random access memory. But what exactly is RAM?

Simply put: The random access memory (RAM) is the ‘working memory’ of technical devices which include computer tech­no­logy. As in the human brain, the working memory is a short-term memory in which the operating system of a device tem­por­ar­ily stores all data of running programs and processes. RAM serves as a computer’s short-term memory, so to speak, and supplies the processor with the data it needs to calculate the processes and programs that are being executed.

Even in­ter­me­di­ate versions of, for example, an Excel table are stored in the RAM memory and can be called up by the processor at any time. How fast the computer works depends largely on the read and write speed, as well as the data transfer rate and storage capacity of the RAM. If the random access memory is busy, you may see a spinning wheel or similar visual displays. In this case, the computer indicates that it is working but has not yet com­pletely retrieved the required data from the RAM.

The diagram above il­lus­trates the function of working memory. It is best explained using the example of an Excel spread­sheet. If you open an Excel spread­sheet that’s stored on the hard disk, the program – in this case Excel – copies the data into the RAM memory. The processor now accesses this data and processes it. In the process, the RAM sends the data to the processor via so-called ‘data buses’. This is quicker via the RAM, as the read and write access is much faster than when accessing the hard disk. As soon as you have finished your Excel work and clicked on ‘Save’, the computer stores the data from the RAM on your hard disk or another storage medium.

Data that you use es­pe­cially fre­quently when working on the computer is tem­por­ar­ily stored by the working memory in the cache. The cache is a small part of the RAM that is directly connected to the processor. This ensures par­tic­u­larly fast access. If your working behaviour changes, the working memory auto­mat­ic­ally replaces data that is used less fre­quently with the data that is used more fre­quently.

The more RAM a computer has, the faster it will run. But naturally it’s not only the per­form­ance that increases: devices with more powerful random access memory are also more expensive. That’s why you should check in advance how much RAM you actually need. In turn, this depends on the kind of work you do and how many programs are running at the same time.

For a tablet that is only being used to surf the internet, for example, 2 GB of RAM are more than enough. If you’re buying a computer for pro­fes­sion­al use, for example to power more complex tasks like video editing or game de­vel­op­ment, then an in­vest­ment into 8 GB or 16 GB or RAM is well worth it.

As a rough guide, you can stick to the following values:

• 4 GB RAM: If you are using your device primarily to surf the internet, to send email, or to work with Office ap­plic­a­tions, then 4 GB of RAM are suf­fi­cient.
• 8 GB RAM: 8 GB of random access memory are ideal if you use your computer a lot and like to have several programs running at the same time. Most current games or ex­tra­vag­ant ap­plic­a­tions will also be covered with this amount of working memory.
• 16 GB RAM: 16 gigabytes RAM is suitable for intensive gaming and compute-intensive tasks like video editing and pro­gram­ming.

If you already know which programs you’re using before pur­chas­ing the device, then it is re­com­men­ded to follow the minimum re­quire­ments of these ap­plic­a­tions.

For smart­phone users, 2 to 4 GB of RAM is usually suf­fi­cient. This amount of memory is usually already in­teg­rated in cheaper Android mobile phones. Apple equips its smart­phones, such as the current iPhone XR, with 3 GB of RAM. There are also smart­phones with 8 GB RAM, although these can be assigned to the high-end segment.

RAM has been around since the dawn of computing. Over the course of time, sci­ent­ists have re­peatedly developed new types of RAM that consume less energy and at the same time have a higher capacity and speed. Already in the late 1990s and early 2000s, you could choose between static RAM (SRAM), dynamic RAM (DRAM), and syn­chron­ous static RAM (SDRAM).

Today, ‘DDR’ type RAM is typically installed in PCs, while pro­fes­sion­al work­sta­tions and servers are pre­dom­in­antly based on ‘ECC RAM’.

In addition, a dis­tinc­tion is made between buffered and re­gistered RAM, as well as DIMM, SO-DIMM and NV-DIMM.

‘DDR’ stands for ‘Double Data Rate’. And that’s exactly what DDR RAM is all about. The speed at which the buses exchange data between RAM and processor can be doubled. Currently, DDR5 with up to 50 GB/s is already in the starting blocks, whereby the number at the end always indicates the re­spect­ive gen­er­a­tion – in this case, the ‘5’ stands for the fifth gen­er­a­tion of DDR memory.

‘ECC-RAM’ in turn stands for ‘Error Cor­rec­tion Code’. If the RAM detects errors in the data, it corrects them in­de­pend­ently. While non-ECC memories always have an even number of chips, an ECC RAM is equipped with one ad­di­tion­al chip per eight memory modules. This ad­di­tion­al chip performs the error detection. As mentioned above, this type of memory is used almost ex­clus­ively in servers and pro­fes­sion­al work­sta­tions. For example, banking systems use ‘ECC-RAM’ to ensure that the amount of money arrives at the right des­tin­a­tion.

While with un­buf­fered RAM (un­re­gistered, UDIMM) the chipset of the mainboard selects the correct memory locations for the requested data, with re­gistered RAM (RDIMM) the same is done by two register chips installed on the module. This type of RAM therefore carries out the al­loc­a­tion in­de­pend­ently and in doing so relieves the chipset of the mainboard.

Re­gistered RAM is often found in the server en­vir­on­ment. Un­buf­fered RAM, on the other hand, is more suitable for devices with little RAM. If the working memory is larger and also the number of RAM modules, the load on the chipset of the mainboard increases, as each RAM module requires the same number of address lines.

DIMM stands for ‘dual inline memory module’. This means that the golden contacts on the underside of the RAM module are capable of transmitting different signals and thereby enable a faster exchange between the random access memory and the processor. Unlike the SIMM (single inline memory module), the front and back sides are not elec­tric­ally con­duct­ively connected.

The following types of DIMMs can be installed in computer devices:

• UDIMMs: This refers to the already mentioned un­buf­fered RAM.
• RDIMMs: re­gistered RAMs
• SO-DIMMs: This random access memory is suited for notebooks and smaller computers due to its smaller building blocks and its reduced energy use. The ‘SO’ in the name stands for ‘small outline’.
• NV-DIMMs: These are special RAMs – if you dis­con­nect your device from the power supply, the data remains saved in the working memory and will be available to you again after turning the power back on. ‘NV’ stands for ‘non-volatile’.