RAM Memory : Functions, How it Works, and Types
RAM Memory : Functions, How it Works, and Types

RAM Memory : Functions, How it Works, and Types

On desktop and laptop computers (or other types of computers) have he type of storage media. The storage media is the primary storage media (primary) and secondary storage media.

RAM ( Random Access Memory ) is one of the main types of storage media in a computer, where data can be accessed randomly ( randomly ) regardless of the location of the data. RAM memory is volatile which can only store data if it has electrical power.

SO-DIMM memory module. Credit: wikipedia
SO-DIMM memory module. Credit: wikipedia

The amount of data that can be accommodated in RAM memory depends on the RAM memory capacity. RAM memory which has a capacity of 8 GB can certainly store more data than RAM memory with a capacity of only 2 GB or 4 GB.

Therefore, a large RAM memory capacity is one of the factors for optimal computer performance. Because, to run various application programs, sufficient RAM memory capacity is needed so that a lot of data can be stored.

Types, How It Works, and Components in the RAM Module

Table of contents

  • RAM functions on the computer
  • How RAM memory works
  • RAM memory component
  • Difference between DIMM and SO-DIMM memory
  • RAM memory type
  • Memory timings

RAM functions on the computer

RAM has the main function as a temporary storage container for data that will be processed by the CPU before being displayed in the form of information that can be recognized by the user . RAM memory also functions as an intermediary medium between the CPU and the boot media or secondary storage media.

This is because secondary storage media such as hard disks , flash drives , or CD / DVDs have limited data access speeds. If the processor has to access files , process, and store data on these storage devices directly, the computer system will run very slowly.

Some of the other RAM functions include

Supports multitasking

Multitasking is a system state that can run more than one application at the same time. When multitasking, RAM will be filled with a lot of application program data that is processed by the CPU in turn.

In order to be able to multitask comfortably, you must use a large capacity of RAM so that it can accommodate more data for applications that are running.

As an alternative to IGP VRAM

Modern processors are now equipped with IGP (Integrated Graphic Processor) as an easy (and inexpensive) display component solution. That way, PC users no longer need to buy a separate graphics card / discrete GPU which costs a lot more.

In order to run properly, IGP also requires VRAM. However, due to space constraints, the CPU’s built-in IGP is not accompanied by VRAM. So, IGP will take advantage of part of the main memory capacity (RAM) as VRAM.

If you decide to use IGP on the CPU, you must use a large capacity RAM to accommodate the system requirements and IGP VRAM allocation. You are also advised to use high speed RAM to increase IGP performance.

How RAM memory works in a computer

When a user wants to run an application program, the data or files needed to run the program will be taken from the secondary storage media (Hard disk / SSD). Then, the system transfers the data to RAM memory for further processing by the processor . After processing is complete, the processor will display the results to the output device or return them back to the storage device.

If the amount of data to be accommodated exceeds the RAM memory capacity, the operating system will perform a swap or “temporary move” procedure . The data will be temporarily moved to a space in secondary storage, which is called a swap file or virtual memory .

Generally, data that is moved to virtual memory is active program data with low priority, such as applications or services running in the background . The swap process can cause computer performance to be not optimal so that the system runs slowly. To prevent this problem, use RAM memory with a capacity according to the specifications required by the operating system or application program that is running.


DIMM or Dual In-line Memory Module is a type of RAM memory module used for modern desktop computers , such as PCs, workstations , or servers . The RAM DIMM memory has separate connector pins on each side of the module. All types of DDR RAM memory have a different number of connector pins and notch positions . The goal is that users do not install RAM memory on the computer because DDR memory is not compatible with each other.

SO-DIMM module size comparison. Credit: wikipedia
SO-DIMM module size comparison. Credit: wikipedia

Not much different from DIMMs, SO-DIMMs or Small Outline DIMMs are a type of memory module used for small computer devices such as laptops , notebooks , tablets , or on Mini-ITX size motherboards . Because it is intended for mobile devices , SO-DIMMs are usually half the size of DIMMs. The number of connector pins is also less than the DIMM version.

Memory type DDR RAM

Currently, generally the RAM memory in circulation is DDR SDRAM ( Double Data Rate Synchronous Dynamic RAM). In the past, there were several types of RAM memory, such as DRAM ( Dynamic RAM), FP RAM ( Fast Page RAM), EDO RAM ( Extended Data Out RAM), and SDR RAM ( Single Data Rate RAM). Usually the older the RAM type, the more expensive the price will be because the number of items is very rare and is no longer produced.

DDR SDRAM can access two instructions at the same time so that it can transfer more data by using one frequency band in full. If the SDRAM memory can only process instructions on positive waves, then DDR SDRAM can process instructions on positive waves or negative waves. Several types of DDR SDRAM memory include


It is an early version of DDR RAM memory in modern computers. DDR SDRAM memory has a transfer rate of up to 400 MT / s with a maximum frequency of 200 MHz. Each DDR DIMM module has 184 pins and a 200 pin SO-DIMM requires 2.5 V.

NameLabelFrequency (MHz)Effective Speed ​​(MHz)Bandwidth (MB/s)


To adjust the performance speed of the processor and graphics interface, memory manufacturers then present DDR2 RAM. The striking difference between DDR and DDR2 is an increase in data transfer speed, increased bandwidth , and a twofold increase in latency .

This change aims to produce optimal performance on computer systems. In addition, DDR2 voltage requirements are more efficient. If DDR memory requires a voltage of 2.5 volts, it is different from DDR2 memory which only requires a power of 1.8 volts.

DDR2 RAM memory is not compatible with previous DDR memory. This is because the DDR2 RAM memory module has a different notch position from the DDR memory module. If the DDR memory module only has 184 pins, the DDR2 DIMM RAM memory has 240 pins and DDR2 SO-DIMM 200 pins. Therefore, DDR2 memory cannot be installed in a DDR memory slot.

NameLabelFrequency (MHz)Effective Speed ​​(MHz)Bandwidth (MB/s)


This type of DDR RAM only consumes 1.5 V of power, which is more efficient when compared to DDR2 1.8v or DDR 2.5v. DDR3 memory already uses 90 nm fabrication technology so that besides being more power efficient, it also has a high density and increases data transfer speeds that are much faster than DDR2.

One DDR3 RAM module can have a capacity of up to 16 GB. Although both have 240 pins, DDR3 and DDR2 are not compatible due to differences in notches , power, and frequency speeds. For DDR3 SO-DIMM has 204 pins.

DDR memory size comparison. Credit: wikipedia
NameLabelFrequency (MHz)Effective Speed ​​(MHz)Bandwidth (MB/s)


DDR4 RAM modules are produced using 30 nm fabrication technology so that they have a higher density, are more power efficient, and increase in data transfer speeds that are much faster than DDR3. In theory, one DDR4 RAM module can have a capacity of up to 512 GB.

However, what is often encountered is a maximum DDR4 capacity of only 32 GB. The power required for DDR4 memory is also only 1.2 V using 288 pin DIMMs and 260 pin SO-DIMMs.

NameLabelFrequency (MHz)Effective Speed ​​(MHz)Bandwidth (MB/s)

The RAM memory speed above is a standard specification and is commonly found on the market. Some RAM memory products, especially premium or high-end class, have specifications that exceed the standard with the XMP feature.

Components on the RAM memory module

  • The SPD ( serial presence detect ) chip is a chip that contains the memory setting profile and standard specifications of the RAM module. SPD is usually detected automatically by the motherboard or BIOS which aims to determine the RAM memory operation process. Some RAM memory manufacturers complete the SPD configuration with the XMP ( Extreme Memory Profile ) feature . With the XMP feature, RAM memory can be adjusted more optimally even more than the standard configuration so that it can produce faster performance. The XMP feature is usually included in premium or high-end RAM memory .
  • RAM chip. The chip is used to store data before it is processed by the CPU. RAM chips are placed in a row on one side of the module ( single side aka single-rank ) or both sides of the module ( double side aka double-rank ) in RAM memory. The number of ranks will determine the number of RAM chips installed.
RAM memory with heatsink. Credit: popularmemory.org
RAM memory with heatsink. Credit: popularmemory.org
  • The heatsink or heatspreader is metal finned to conduct heat generated by the RAM chip. The heatsink covers the RAM chip with the aim of protecting it from overheating which can physically damage the chip. Heatsink is usually used for premium or high-end RAM memory .
  • The notch is a small hole where the latch functions to lock the module in the memory slot on the motherboard . Notches are located on the sides and bottom of the memory module connector. The notch on the connector serves to prevent the memory module from being placed in a slot that does not match the type of RAM memory being used. The type of memory that can be used by a computer system is memory that has a notch that matches the memory slot on the motherboard .
  • RAM memory connector that attaches to the memory slot on the motherboard . Shaped like a copper yellow pin on the bottom of both sides of the memory module. This memory connector is quite sensitive to debris that can cause system errors . If the connector is dirty, we can clean the connector by rubbing a rubber wiper.
  • In some RAM modules, especially those intended for the premium class, they are usually equipped with RGB LEDs. This is intended as an additional aesthetic feature on the computer system in the form of colored lights. In fact, the color can be changed according to the wishes of the computer user.

RAM memory timing

In general, RAM memory performance is determined based on its transfer speed. The data transfer rate of a RAM is usually known from the clock speed or frequency speed multiplied by 16. For example, DDR3-1600 with a frequency of 800 MHz has a transfer rate of 12800 MT / s.

RAM memory timing label. Credit: bcot1.com
RAM memory timing label. Credit: bcot1.com

Apart from the clock speed, what affects the performance of a RAM is the timing factor . Timing in RAM memory in general (usually listed on the module specification label) is a representation of complex processes in a RAM while working.

The timing is divided into 4 numbers which are written sequentially, namely CL, TRCD, TRP, and TRAS. Sometimes some RAM memory also lists a fifth number which is known as the command rate (usually written as 1T).

Examples of timings in RAM memory are for example 7-8-8-24. Think of RAM as a table that has columns and rows and contains space to store various data.

  • CL or CAS Latency is the time it takes for RAM to respond to commands from the processor. The smaller the CL value, the better the RAM performance. CL is the most important number on RAM memory performance compared to other numbers on memory timings .
  • TRCD or ” RAS to CAS delay ” is the time it takes for RAM to activate between rows and columns during data processing. The smaller the TRCD value, the faster activation before processing data in RAM memory.
  • TRP or ” RAS precharge ” is the time it takes for RAM to move to the next row. The smaller the value, the faster the performance of a RAM
  • tRAS or ” active to precharge delay ” is the time it takes for RAM to wait for the next instruction to enter after the previous instruction is finished. The tRAS value is at least the sum of the three previous timing values (because it is the last process after going through the previous three processes) with a tolerance of several clock cycles. As in the previous timing example : 7 + 8 + 8 = 23. The TRAS value is 23 + 1 = 24. Adding the value of 1 is for stability. Because if the value on timing exceeds the limit of RAM memory capacity, as a result data processing can be interrupted which leads to errors in the system.

Command Rate (CMD) is the time it takes for the first time the RAM memory is active. By default, CMD is usually set at a value of 1T which is the fastest lag time. Just like other values, the smaller the CMD number means the better the performance of a RAM memory.

That’s a brief explanation of the function, how it works, and technical specifications of RAM memory on a PC. May be useful…

1 comment

  1. Nice article
    I would like to know
    If one connector pin (out of 240) of
    ddr 2 1066 ram is damage will the ram work.

Leave a Reply

Your email address will not be published. Required fields are marked *