Understanding Computer Memory

I've received a lot of different questions regarding computer memory, or RAM. RAM stands for Random Access Memory and it's what the computer uses to run programs.
Published: Sep 22, 2005
Author: Michael E, Callahan

This question submitted by Patty Ames, Richard Evans, Amy Redmond, Bill Janus and numerous others. Names are used with permission.

I've received a lot of different questions regarding computer memory, or RAM. RAM stands for Random Access Memory and it's what the computer uses to run programs. Unlike disk space, or storage memory, things in RAM are transient. If the power goes off everything in RAM is gone. There seems to be a lot of misconceptions about RAM, so I'm going to do my best to answer the most common questions I've received.

How Much RAM?

This is probably the most common question. Nearly every program you'll ever look at will tell you how much RAM it needs. Many will give you a minimum amount and they often suggest a larger amount that would be better. So, for example, a program might say it requires 128MB of RAM and 256MB is suggested. Well, read that as it can work with 128MB but it works much better with 256MB. And that's true for computers in general. In the early 1980s there was a quote that went around, attributed to "Anonymous" that said, "You can never have too much disk space or too much RAM!" And truer words were never spoken. All of my computers, including my laptops, have 1 gigabyte of RAM. If you're buying a new computer and you're on a limited budget, don't skimp on RAM. Get a cheaper graphics card or a smaller monitor, but don't cut back on RAM. In my opinion, it's RAM that is the key factor in computer performance. Trust me on this, when in doubt get more RAM -- a minimum of 512MB if you're using Windows XP.

What Type Of RAM?

The first thing you have to know is that all RAM is not created equal. There are different types and you need to put the correct kind in your computer. One thing that many users don't understand is that RAM has a speed. If you just slap some RAM chips into your computer without checking to make sure their speed matches what you already have, you're going to encounter problems. If you want to add more RAM to your computer, check the manual or contact the manufacturer. In this way you can find out the correct type of RAM to use. When dealing with memory you're going to encounter a number of terms. Without getting too technical, I'll explain what some of these mean.

  • RAM - Random Access Memory
  • EDO or EDO RAM - Extended Data Out
  • SDRAM - Synchronous Dynamic RAM
  • DDR - Double Data Rate
  • DIMM - Dual Inline Memory Module
  • SO-DIMM - Small Outline DIMM (laptops)
  • DDR2 - Double Data Rate - the second generation
  • SIMM - Single Inline Memory Module

You may not really need to know what these things mean, but I thought at least you should understand what they stand for. That way when some technical guy says, "You need a 512MB DIMM of DDR SDRAM" you won't be totally in the dark. SIMMs were used in earlier computers like Pentium IIs. Other types, like EDO and DDR, were designed to help speed up the computer by having the RAM keep pace with the processors. The key thing to remember is that you do not put just any RAM chip into your computer. Always be sure to check with someone who knows before installing RAM. Why? Because while the speed and technology of RAM chips has changes, in many cases they still have the same number of pins on the bottom. That means it could be possible to put a very old chip in your newer computer. So, be safe and check!

Flash Memory

One memory type I haven't covered is flash memory. Flash memory tends to be very small and it's used in places you might not even imagine. You'll find flash memory in you Palm Pilot, your Pocket PC, your cell phone, your game console and many other places. Unlike the conventional RAM we've been talking about, flash memory retains what's on it when the device is turned off. In this sense, flash memory really acts more like a hard disk than true RAM. A few examples of flash memory include:

  • Compact Flash card
  • Secured Digital (SD) cards
  • Memory Sticks
  • xD Picture cards

Even as I write this there are companies working on ways to make all types of memory smaller, faster and cheaper. Memory continues to evolve and change. And ironically, it seems that the smaller storage media becomes the more it holds. Back in the early 1980s 8-inch disks held 160K, then 5.25 inch disks held 360K. As time went on the 3.5 inch disk came out first at 700K and then at 1.44MB! Wow, that was a lot back then. Now there are flash drives that can hold up to 4 gigabytes. My keychain hard drive holds 512MB, and the SD cards for our digital camera hold 1 gigabyte. And these cards aren't much bigger than a postage stamp. Amazing.

Summing It Up

RAM continues to evolve as computers get faster and smaller. Programs need more RAM and so does the operating system. RAM comes in different classifications and speeds and you need to make sure you install what's right for your computer. My advice is to always go with at least 512MB of RAM. And when in doubt, always check your manual or ask the manufacturer before adding RAM to your computer.

I'd like to thank Patty Ames, Richard Evans, Amy Redmond, Bill Janus and numerous others for asking this question. Names are used with permission.

If you have a question on how to do something on the computer you can submit it via e-mail by clicking HERE. You will not receive a reply, but all topics will be considered.

About Michael E, Callahan

Michael E. Callahan, known around the world by the trademarked name Dr. File Finder, is regarded as the world's leading expert on shareware. Dr. File Finder works with software programs and developers full-time, and in the average year he evaluates 10,000 programs. Since 1982 he has evaluated over 250,000 software and hardware products. Mr. Callahan began evaluating software online in 1982 and no one has been at it longer. He currently works doing online PR and marketing for software companies, and is the Senior Content Producer for Butterscotch.Com.

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