The Basics of Computer Memory

Computer memory is a storage area for both program code and data which is currently in use.  Computer programs can write and retrieve information from memory in any order, allowing for fast data retrieval and manipulation.

Computer memory is called Random Access Memory (RAM).  Data in RAM can be accessed randomly rather than sequentially.  This means that data can be accessed from different locations at the same speed.  Other storage media like CD-Rom and hard drives have to wait for the drive to spin to the correct location before data can be accessed.

Because of the fast access time that RAM offers, installing more RAM in your computer will make it significantly faster.  This is because the computer can put more program instructions into memory and rely less on information stored on the slower hard drive.

Increasing the amount of memory is one of the best ways of improving computer performance.  If you compare two computer systems identical except for the amount of RAM, the one with the greater amount of memory will be faster.

How Much RAM?

So if more RAM is better, how much is the best?  The simple answer to that question is: As much as possible.  In the real world, though, once you reach a certain threshold you are likely to see diminishing returns on your memory investment.

Think of 512 Megabytes (MB) as the standard for a computer with the Windows XP operating system.  The Linux operating system requires significantly less.  Linux has several advantages over Windows (free, more stable) but for the most part remains on the sidelines.  Most PCs today use Windows.

With 512 MB of memory, you should be able to comfortably run several applications at the same time (multi-task).  You can surf the Internet, download MP3s, run a word processor and check your email without any noticeable sluggishness.

Some applications are more memory hungry than others, however, so if you notice your computer slowing down, you might consider adding more memory.  Before going that route however, try defragmenting your hard drive.  A fragmented hard drive is another major cause of slow performance.

Types of RAM

DDR SDRAM is currently the most popular type of memory module.  DDR stands for Double Data Rate and means that the memory can be accessed two times per clock cycle.  SDRAM stands for Synchronous Data Random Access Memory which has been the standard for memory modules for close to 10 years now.

If you wish to add more memory to your computer, you must buy modules with the correct contact layout.  The most common form factors are 168 pin, 184 pin and 200 pin.  It is essential that you know which type your motherboard accepts before buying new memory.

You also need to know if there are free slots on you motherboard for accepting new memory modules.  If all the slots are used you will have to replace one or all of the current modules for higher capacity ones.  If there is at least one free slot you can just buy a new memory module and insert it in the empty slot.

Careful though.  Some motherboards are designed to accept both SDRAM and DDR SDRAM but the two types cannot be mixed – you have to use all SDRAM or all DDR SDRAM.  Check the motherboard manual to see exactly what kind of memory you can use.