Memory

Memory

Computer memory is any physical device capable of storing information temporarily or permanently. For example, Random Access Memory (RAM), is a volatile memory that stores information on an integrated circuit used by the operating system, software, and hardware.

• What does computer memory look like?
• Volatile vs. non-volatile memory
• What happens to memory when the computer is turned off?
• Memory is not disk storage
• How is memory used
• Why is memory important or needed for a computer?
• Types of RAM
• Related memory pages.
• Computer memory help and support.

What does computer memory look like?

 

Below is an example picture of a 512 MB DIMM computer memory module. This memory module connects to the memory slot on a computer motherboard.

Volatile vs. non-volatile memory
Memory can be either volatile and non-volatile memory. Volatile memory is a memory that loses its contents when the computer or hardware device loses power. Computer RAM is an example of a volatile memory and is why if your computer freezes or reboots when working on a program, you lose anything that hasn't been saved. Non-volatile memory, sometimes abbreviated as NVRAM, is a memory that keeps its contents even if the power is lost. EPROM is an example of a non-volatile memory.

What happens to memory when the computer is turned off?
As mentioned above because memory (RAM) is a volatile memory when the computer loses power anything stored in RAM is lost. For example, as you are working on creating a document it is stored in RAM if it is not saved to a non-volatile memory (e.g., the hard drive) it would be lost if the computer lost power.

Memory is not disk storage

It is very common for new computer users to be confused by what parts in the computer are memory. Although both the hard drive and RAM are memory, it is more appropriate to refer to RAM as "memory" or "primary memory" and a hard drive as "storage" or "secondary storage."

When someone asks how much memory is in your computer, it is often between 1 GB and 16 GB of Random Access Memory (RAM) and several hundred gigabytes of even a terabyte of hard disk drive storage. In other words, you always have more hard drive space than RAM.

How can I learn more about computers?

How is memory used
 
When a program such as your Internet browser is open, it is loaded from your hard drive and placed into RAM, which allows that program to communicate with the processor at higher speeds. Anything you save to your computer, such as a picture or video, is sent to your hard drive for storage.

Why is memory important or needed for a computer?
 
All of devices on a computer do not operate at the same speed and computer memory gives your computer a place to quickly access data. If the CPU had to wait for a secondary storage device like a hard disk drive the computer would be much slower.

Types of RAM
Some of the more common types of memory chips for computers are listed below.

• EDO RAM
• SDRAM
• DDR RAM
• DDR2 RAM
• DDR3 RAM
• DDR4 RAM

These types of memory all fall into the general categories of SIMM or DIMM.

Related memory pages
Determining how much RAM is installed and available.
How much memory or RAM should my computer have?
Determining available hard drive space.
Memory buying tips
Computer memory manufacturers.
Computer memory help and support.
GDDR, Memory capacity, Memory terms, RAM, Primary storage, Processing device, ReadyBoost, TSR, Virtual memory, Volatile memory

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How to install computer memory (RAM)

How to install computer memory (RAM)

Memory buying tips

Computer memory buying tips.

Before getting started

• Ensure you are familiar with ESD and its potential dangers.
• When installing the memory make sure the computer is off and unplugged.

Locate memory slots and install memory

• DIMM memory installation steps (most common)
• RIMM memory installation steps
• Notebook (laptop) memory installation steps
• SIMM memory installation steps

DIMM (DRAM, SDRAM, and DDR) memory installation steps

Note: When handling memory, hold it by each end of the module and be careful not to bend it, flex it or drop it while handling it. When pushing the memory into the computer do not apply an excessive amount of pressure, doing this could cause damage to the memory module as well as the slots on the motherboard. Finally, when installing the memory, distribute the pressure evenly by pressing on both corners of the memory module.

Once the memory has been purchased, locate the memory slots on the computer motherboard. If no memory slots are available on the computer, one or more memory modules must be removed before the memory can be installed.

Note: If the computer has a small form factor, it may be difficult to access the memory slots. You may have to temporarily remove cables or expansion cards before you can access them easily. When disconnecting anything from the computer make sure you can remember where each cable and card goes.

Each slot on a motherboard that supports a DIMM is a bank, therefore the computer will work if just one memory module is purchased.

Examine the memory module before installing it into the computer. At the bottom of the memory module you should notice one or more notches at the bottom of the card, like those shown in the picture below.

Make sure that the notches match up with the memory slot you are installing the memory into. These notches allow the memory to only be installed in one direction and if it is not a compatible memory will not match up at all.

After verifying the notches and direction the memory needs to be installed move each memory slot tab out or away from the memory module. These tabs will snap into place as the memory module is installed.

Once these tabs have been moved out, push the memory module in at a vertical or 90 degree angle. As the memory module is being pushed, the two tabs should snap and hold the memory module into place.

After the memory has been installed in the computer, plug the computer back in and turn the computer on. As the computer is booting the memory should be automatically detected and setup. If you have any difficulties with the memory being detected or setup, enter the BIOS setup and configure the settings manually or make sure the memory is being detected.

RIMM memory installation steps

What makes RIMM memory modules different from DIMM memory modules is the C-RIMM memory module. This module allows the computer to have a continuous flow of data. When installing a new RIMM remove the C-RIMM. This module is a small circuit board and has a few or no chips on it.

Once the C-RIMM module has been removed and the two tabs are in the outwards position, push the RIMM memory module in at a vertical or 90 degree angle. As the memory module is being pushed, the two tabs should snap and hold the memory module into place.

Installing notebook (laptop) memory

Before the memory can be installed into a notebook the memory slots must be located. If you are unfamiliar with where these slots are located, below is a listing of possible locations:

On a compartment on the bottom of the laptop.
Under the keyboard.
Within the computer.
If you are unable to locate the slots after looking at each of the above recommendations, we recommended you contact the computer manufacturer for additional help and information.

Once the slots have been located, the next step will be to install the computer memory. Today, most laptops follow the same memory installation.

Because laptops are thin when compared to a desktop computer, the memory banks are horizontal with the laptop. The memory must be inserted at an angle, about a 75-degree angle and once in the slot press down on the memory to snap the memory into place. The memory should also lay horizontally with the computer.

SIMM memory installation steps

30 and 72-Pin SIMM memory modules must occupy a bank. Computers that use 72-Pin SIMM's have two sockets as one bank. Therefore, two memory modules of equal value must be installed in pairs, unless instructed otherwise by the computer or motherboard manufacturer.

The installation of most SIMM memory is the same. The memory must be entered at an angle, about a 75-degree angle and while still in the memory slot, moved to a vertical or 90-degree angle. As the memory module is moved to a vertical position it should snap into place. When installed, ensure that both sides of the memory module are snapped into place. If a memory module is not installed properly or not all the way in, this could cause damage or the computer.

It is recommended that the larger memory modules be installed in the lowest available banks. For example, if the computer has a pair of 4 MB memory modules and you are installing two 32 MB memory modules make sure the 32 MB memory modules are in bank 0 and 1 or 1 and 2.

Note: Some computer manufacturers may require SIMM modules be installed in a certain order. So, if your new computer memory installation does not work, consider switching the location of the memory.

Set memory in BIOS
Once the memory appears to have been successfully installed into the computer, place the case back onto the computer and connect the keyboard, monitor, and power to the computer (we recommend that you do not connect all the cables yet, if problems are experienced you may have to disconnect all the cables again).

As the computer is booting, enter the BIOS and either set the memory to its proper settings or verify that the computer's memory is being properly detected. Once changed or verified, save the settings, exit BIOS and reboot the computer.

Additional help and information about the BIOS can be found on our BIOS page.

TroubleshootingComputer memory help and support.

Additional information
 How do I remove computer memory in my computer?
How to install computer hardware.
See our memory definition for further information and related links.
Computer memory help and support.

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