MEMORY Chips

MEMORY is only one of the REQUIRED hardware components of a PC. It is not more important, nor less important than the other components of your PC. But much of our modern day software will not operate efficiently, if at all, without "gobs" of memory.

MEMORY is a term that is used to represent storage that has "almost" instantaneous access by the CPU or other processor. Every computer will have some type of memory. However, the memory we speak of the most often is Random Access Memory (RAM). RAM is the primary memory used when we "boot" (start up) a microprocessor and the PC's operating system and device drivers are loaded into RAM.

RAM has many functions, but its primary function is to store programs and drivers for the various system devices. It is probably the most important type of memory in your PC.

Courtesy Kingston Technology Corp.

When you enter a command from your keyboard, the CPU (microprocessor) processes the command and calls for data (a program or data file) to be copied from a storage device (hard disk, floppy, CD-ROM, etc.) into memory, where it is stored temporarily until the CPU needs it. The memory then provides the data to the CPU more quickly than from the storage device. This data may be a program and actual data. This bulk memory is called "RAM".

The RAM is divided into multiple parts (locations, not types):

  1. Conventional Memory (location 0 thru 640 KB)
  2. High (Upper) Memory (641 thru 1 MB)
  3. Extended Memory (addresses above 1 MB)
  4. Expanded Memory (sometimes).

RAM, itself, usually consists of Dynamic Random Access Memory (DRAM) chips mounted on Single In-Line Memory Modules (SIMM) boards or chips. A 30 pin SIMM can hold up to 4MB and a 72 pin SIMM can hold up to 32 MB of memory.

Numerous "types" of memory exist and your specific PC may contain several types of memory for different purposes. Some of the terms you will hear are: RAM, DRAM, SRAM, EDORAM, SDRAM, ROM, PROM, EPROM, EEPROM, FLASH, internal and external cache, etc. These terms will be discussed below and in the "Terms and Definitions" selection.

Before I confuse you more, let me give you a table which will list these types and the normal uses for them:

Memory Type Use
ROM BIOS, CMOS
RAM Main Memory
DRAM Chips on SIMM boards or Motherboard (Main Memory)
SRAM CACHE
EDORAM Main Memory
SDRAM CACHE (Pentium w/MMX may have SDRAM as main memory)
FLASH Normally, it is memory on a card. The size of a PCMCIA card.

Lets discuss some of them below. Click on the type of memory for a short discussion.

    Some of the types of memory are:

  1. RAM (Random Access Memory)
  2. ROM (Read Only Memory)
  3. Cache Memory
  4. Conventional, High, and Extended Memory
  5. Expanded Memory
  6. Flash Memory
... and the list goes on. The difficulty is understanding when and how they are used, and even when one term means one type of some other term.

HOW MUCH MEMORY DO YOU NEED?

No one can say exactly - you need to know things about your system operating system, the type of applications you will run on your PC (graphics, multi-media, word processing, etc). Let me give you a few hints:

Quantity GENERAL USES
4 MB DOS applications, maybe Windows 3.1, a few old word processing packages, etc.
8-12 MB Windows for Workgroups, small word-processing, E-Mail, only a few (1 to 3) applications open. Maybe an Internet package such as Internet Explorer or Netscape, AOL, etc. Will be somewhat inefficient.
12-16 MBWindows for Workgroups, supposedly Windows 95 (not really!), Word processing, E-Mail, WEB interfaces, FAX, spreadsheets, and low level graphics applications. Few applications open simultaneously.
16-24 MBYou can now load Windows NT Server, Windows NT Workstation, and Windows 95. NT Server works inefficiently at this level. Some number crunching, spreadsheets, E-Mail, WEB browsers, some graphics and audio-visual (but weak).
24-32 MBNow you can do heavy applications. Spread sheets, statistical analysis programs, large databases, and multiple applications open. Even a little graphics and games - a an acceptable speed.
32-64 MBStarting into decent graphics, with word processing, page layouts, even some good "audio visual" type applications.
64-128You are now read for medium to high level graphics and animation - if you have the other necessary hardware. Photo editing, multimedia, word processing, illustration graphics, the whole nine yards!
128+ MBNow you are talking! This is the level for efficient Windows NT Servers with many users. Multimedia and about everything else!

Just remember this: You can have all the RAM memory you can install; but, if you do not have adequate internal and external cache, good video cards, a 32-bit or 64-bit bus, etc., you will still operate somewhat slower.

What do you need to know before purchasing memory .

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