What is it?
To visualize the function of memory in your computer, think of your computer's processor as a worker standing at a workbench. If the worker needs a tool that isn't nearby, he must search for it and hopefully find it quickly. If it isn't immediately available, he may have to turn around and open a locker to get the tool, which takes a little more time. However, if the right tool isn't in the nearby locker, he may have to walk all the way outside to a tool shed to get it, which takes even more time.

In the same way, your computer's processor needs data to work, but it cannot work efficiently if it has to repeatedly stop and search for the needed data, which is like having to walk all the way outside to the tool shed over and over again for each tool. Computer memory is like the locker and the workbench -- places to store information where the processor can get to it quickly and continue working without pause. Storing more data in memory means it's more accessible and that the computer won't have to slow down as often to go looking for that data.

Be careful not to confuse RAM (Random Access Memory) with your hard drive. Both perform a storage function and are measured in megabytes or gigabytes. These similarities both contribute to the confusion, but they perform distinctly different functions. Simply put, RAM temporarily stores data while the hard drive permanently stores it. Anytime you save a file, the data is stored on your permanently hard drive.

What exactly is stored in your computer's RAM? Any open software application, such as a word processor or Internet browser, is temporarily stored in memory. Along with these programs, any data required to operate them is also stored in memory for fast retrieval. More RAM allows your computer to store more data and retrieve it more quickly than with less RAM. With more RAM, you can operate more applications simultaneously on your computer without consuming all its vital resources.

If there is not enough space available in your RAM, "thrashing" can occur. This is when your computer has to kick out some data from its RAM in order to create space for other data that it needs more urgently. Memory thrashing greatly slows down the computer since it has to wait for the slow hard drive to find the information it needs and load it into memory. More RAM avoids forcing the computer to search the hard drive to find the necessary information.

The memory used in today's computers usually comes in small rectangular modules that are installed in sockets on a computer's motherboard. There are different types of memory, including FPM DRAM, EDO DRAM, SDRAM, and RDRAM, each of which has its own distinctions and advantages. Most computers only support one type of memory, but some also support two types.

Why would I want it?
Adding more memory to your computer produces an overall improvement in its performance. It lets the computer run more programs simultaneously, so you can surf the Internet, listen to an MP3 music file, and play a game without slowing down the system. More memory also helps your computer to run complex software even faster, such as recent 3D games or voice recognition programs.

How do I install and use it?
Before installing any memory, be sure to carefully read the installation instructions that accompanied the module(s). If no instructions are included, you may find memory installation instructions in the manual for your computer or your motherboard. Or, visit the manufacturer's Web site for instructions.

Installing memory is usually a fairly simple procedure, but is not recommended for the novice computer user. Mishandling memory or your computer can result in irreparable damage to both. If you are not sure about your ability to install memory correctly, take your computer to an authorized technician/dealer for service.

Unpack and inventory all the components that are in the box, which normally includes one or two memory modules and often a sheet of paper with the installation instructions. Before handling the memory modules themselves, touch a grounded piece of metal to discharge static electricity from your hands -- static can damage sensitive computer components.

Turn off your computer and unplug it from its power source.

Open the computer case to access the internal components; this may require unscrewing several screws that hold the cover in place. WARNING: Opening your computer may void your warranty. Carefully review your computer's documentation for instructions.

Locate the memory slots on the motherboard and take notice of the numbering of each bank of slots. Memory banks are usually numbered starting with zero, then one, and on up, and you should always install new memory in the lowest-numbered bank available. For example, if there are three banks of memory slots available, and memory is already installed in bank zero, you should install the next memory upgrade in bank one instead of bank two. Sometimes the numbers are printed beside the memory slots on the motherboard, and sometimes they are numbered in the manual for the computer or the motherboard. If you have no way to determine the order in which the memory banks are numbered, then you can use a trial and error method. Your computer may not recognize memory installed in the wrong memory bank, or it may produce computer errors, but it will not be damaged simply from being in the wrong memory bank. If your computer fails to recognize the new memory, or you notice erratic computer behavior, try simply repeating the installation procedure and moving the memory to a different socket.

When you have located the correct socket, insert the memory module as shown in the instructions. Different types and sizes of memory modules are often inserted in slightly different ways. There is no single standard method. However, never force a memory module into the slot. If it seems a bit resistant, handle it firmly but gently, and try rocking it gently into the socket one corner at a time. Lock the module into the socket as shown in your instructions. Repeat this procedure for any additional memory modules you may have.

Replace the cover to your computer case, plug in your computer, and then turn on the computer and monitor. Many computers perform a memory count upon start-up. At this stage, you may see the computer recognizing the added memory. If you hear a series of beeps and the computer refuses to boot, there might be a memory error or an incorrectly installed memory module. Go back and check all the installation steps. If the problem persists, try removing the new memory to see whether the error is related to it. If you have followed the installation procedure correctly and you continue to get an error upon start-up, you may need to ask for technical support from the memory's manufacturer or from a trained technician.

If there are no problems and the computer starts up normally, then you're finished -- the computer will use the new memory automatically, without any setup or configuration by software required.

How do I go about buying it?
The fastest and easiest way to locate compatible memory upgrades is to visit Memory Express. You can locate the brand name, the product name and the model number of your computer, and generate a list of memory modules that have been pre-tested for compatibility with your computer.

If your computer is an off-brand, is home-built, or you cannot locate your model in Memory Express, you should consult the manual for your computer or motherboard. If no manual is available, contact the manufacturer for assistance.

Determine the following memory components:

		Type of memory
		Speed requirements, if applicable
		Non-parity or parity
		Total memory the computer supports
		How much memory can be on a single module
		Metal contact points (gold or tin)

When you have learned these specifications for memory in your computer, shop for memory modules that match those requirements. If you are unsure of the memory your computer requires, contact a trained and authorized technician for assistance.

What products are most recommended?
Selecting memory upgrades for your computer is not like, say, choosing a graphics card. Shopping for memory is usually a matter of finding modules that are compatible with your system instead of comparing the performance and features of different modules. If you have a choice between different modules that are all compatible with your computer, we suggest comparing manufacturer quality, especially in terms of the customer service and warranty they provide for their memory products. A manufacturer's level of confidence in its product is reflected in the length of their warranty coverage, and the highest quality memory modules today should have a warranty of at least five years. Many memory manufacturers offer a lifetime warranty, which is of course even more desirable.