Memory in computer terms is where all the instructions and data that need to be reached at speed are stored. A computer is unusable without memory. The operating system, software, and hardware must be able to use this memory.
There are two basic types of memory on a computer, RAM or Random Access Memory. This is the ‘primary’ memory, and it is on microchips that are connected to the motherboard. These give the CPU (Central Processing Unit) constant access, making it a smooth and fast process. The larger the capacity of the memory chips, the faster a computer can work due to not having to access data and instructions from slower devices such as the secondary memory or storage such as Hard Disk Drives (HDD) or Solid State Drives (SSD).
There are many types of primary memory, ranging from the cache memory built into the CPU to create a fast cache of information ready to be used to EEPROM or easily erasable prom (programmer) that can be programmed and erased on the fly by the programmer.
Double Data Rate 4 Synchronous Dynamic RAM or DDR4 RAM is the most common memory used in computers these days. It has a high rate of access due to the increased bandwidth capabilities over its predecessors DDR2 and DDR3.
The memory capacity on a motherboard is usually between two memory slots in low-end computers and eight module slots in the high-end computers, the norm is four. DDR4 modules can reach the dizzying heights of 64 gigabytes (GB), meaning a total of 256 GB RAM capacity in a four-slot motherboard.
What memory to use?
The most important thing to know is what type of memory the motherboard takes, as the connections are different on the DDR2, DDR3, and DDR4 memory. The next consideration is what the computer will be used for. If it will be mainly being used to surf the internet and for writing emails, then getting 256 GB of DDR4 is going to cost a lot of money, and most of the memory will never be touched.
If intensive graphics are to be accessed, like video gaming or 3D modeling, then get as much as the computer will take, if the budget will take it.
When it comes to upgrading the memory, throw out the old sticks. Putting two 16 GB old sticks in with two new 64 GB sticks will not work as the system will only work as fast as the lower-end memory. Buy all four memory sticks, if that is the number of slots you have, and from the same manufacturer, from the same batch if possible, as this will help prevent problems with installation and usage.
The memory types in use today in modern computer systems are wide and varied and cannot be covered in this small article. Hopefully, this has helped to give the information that can go a small way to helping get the correct memory and provide an understanding of what the memory does, how the computer uses it, and the processes involved.