Random Access Memory is not when you can think of an answer sometimes but not others. It is the memory chip in your computer that holds the information currently running on your PC. For example, if you load up Microsoft Word, your web browser, Tiny Timmy's Transylvania Adventures, or anything else, the ones and zeros that make up that program get shoved into your computer's RAM (memory) to be accessed randomly (thus the "random access" part of the name) to give you what you want. The little known secret of computer performance is that the memory, not the processor, is usually to blame for a system slowdown.

All computers will only accept a certain type and amount of memory, so you need to make sure you know what type and how much your machine can handle. This is a major consideration when buying a new PC, so be sure you ask what the maximum upgradeable memory is, which makes your PC (and your investment) last longer. Another consideration to be aware of is how many memory slots your computer has. Each slot has a maximum as well, so it is always good to know to determine your optimal RAM configuration. In lieu of a knowledgeable salesperson, many websites offer free "memory configurators" to help you find out what kind and how much memory you need.

Let's do the math. If you are familiar with computer terms you might be familiar with some of the most common digital storage sizes:

• 1 Bit = either a 1 or a 0 (which makes up binary code)
• 1 Byte (b) = 8 bits
• 1 Kilobyte (KB) = roughly 1 thousand bytes.
• 1 Megabyte (MB) = roughly 1 million bytes.
• 1 Gigabyte (GB) = roughly 1 billion bytes.
• 1 Terabyte (TB) = roughly 1 trillion bytes.

There are others like Petabyte, Exarabyte, Zettabyte, and Yottabyte, but KB, MB, GB, and TB is what we typically deal with today. RAM generally comes in 1GB, 2GB, and 4GB sticks these days. To give you some perspective, a traditional CD-ROM holds around 700MB of data, so 70% of a gigabyte. That is about 1400 average sized photos, or about 175 mp3's. The rule of thumb is that you should see a marked improvement in computer speed the more memory you have. If you find out your computer has 4 memory slots and accepts up to 4GB of memory, you can assume that each slot holds up to 1GB. You can put 512MB (basically half the 1GB) in each slot and come up with around 2GB of memory if desired. If you have 2 slots and your PC accepts up to 4GB, each slot is up to 2GB each. It is as easy as that.

Programs are usually much smaller, using anywhere from 5,000KB (5MB) to 100,000KB (100MB) if it is a regular program. So, if a program like Firefox's web browser takes up 40,000KB (40MB), that is how much memory is being consumed by it constantly until it is closed. You can see how all the programs you have running would add up quickly. The system also needs a bunch of that memory free for system operations, like background search indexing, system processes, power regulation, etc. If a program is poorly written, it can consume more memory continually as it runs, or take up memory after it is closed. These program defects are called "memory leaks" which doesn't mean the 1s and 0s are bleeding all over the inside, it just refers to the fact that the programmer didn't manage the memory resources well when writing the program. For this reason, if you have 20 windows open at the same time, your PC will run much slower than if you have two windows open. All programs have different memory requirements. Video games typically require a lot of memory to run, since they have to process a lot of intense graphical information quickly. Video games, however, end up using their own type of memory in many systems.

Graphics cards now have their own processors (GPU or Graphical Processing Unit) and memory (GDDR is a newer example of graphics-designated memory), which make graphics cards almost their own computer on an expansion board solely to run high-end graphical applications (that's code for video games and 3D drafting software). This special type of memory is unique because of where it is located and how it is allocated, not because it is that much different in composition from regular computer memory. Having 512MB, 1GB, 2GB, or more graphical memory takes much of the load off the main memory, since all the graphics you see will be processed via the graphics card, its processor and memory. Some graphics cards these days are essentially 2 expansion boards with a processor and memory paired together via a bridging device to give you double the pleasure when running gaming applications primarily.

There is some shared memory built-in to most motherboards, since you need something by default to even install a better graphics card later. Shared memory is when the video subsystem steals memory from the main memory for the PC, making your PC effectively a bit slower, though you may not notice much slowdown at all depending on what type of applications you typically run. That shared video memory portion is subtracted from your installed memory, so 1GB computer memory less 144MB of shared video memory leaves only 866MB or so for your PC to chomp through. Unfortunately, many shared video memory enabled systems don't allow the user to change the amount of memory your video card borrows or limit it so it doesn't take too much memory away from applications you need to run. Adding more memory can help, but will also help the video memory size get bigger too. Beware when buying a shared video memory PC, since some games will not play nicely with a shared situation, especially since many shared video solutions are more generic, and don't have required technologies a slotted expansion graphics card would have, such as Transform and Lighting (T&L) or programmable shaders.

Several well known companies provide memory; some of the top manufacturers are: Crucial, Corsair, Kingston, OCZ, Patriot, and PNY. There a ton of other companies whose products are good, so do a little research; many of the knock-off budget brands will be fine. The main differences in memory you will need to know are:

• What type of memory technology is used in the chip: DDR, SDRAM, EDO, SRAM, etc. Most modern RAM requirements are DDR SDRAM these days in both laptops and desktops.
• What clock speed the RAM is, which is a different specification from your computer's processor speed: DDR 266, DDR 333, DDR 400, DDR 500, etc.. Each generally has a module number associated with it to make it easier: PC 2100, PC 2700, PC 3200, PC 3400, etc. That number will help ensure you get the right one.

 Here are some great resources to help you determine what memory and how much you need:

Memory Configurators

• NewEgg (good deals on memory)
• TigerDirect (click Memory Configurator on the left side)
• MicroCenter (good discounts, usually with rebates)
• Kahlon (good for older systems and discount memory/hard drives)
• Crucial
• Corsair
• OCZ

The last thing to remember about RAM is that you can usually find out what kind of RAM you need by checking out the user's manual or the technical specs on the manufacturer's website. It all depends on the limits of the motherboard (also known as a main board). Your computer is hungry for memory, so feed it more memory, and you won't be sorry.

Photos by: marinm, arminh, and altair.