MARCH 2004 MAXIMUMPC 49
We explain everything you
need to know about RAM,
including how it works and
why some memory works
better than others
èR^
AM. It’s short for random-access memory,
and you already know the basics: Your
system can’t run without it; Windows
XP should have at least 256MB, but 512MB is
better; and faster RAM can improve system
performance if your system is designed to use it.
But how well do you really understand mem-
ory? In this article, you’ll learn how memory
works, how your BIOS and chipset combine
forces to manage memory access, and the pros-
pects for current and emerging memory technol-ogies, from SDRAM and RDRAM to DDR2.
How RAM works
No matter how much RAM is installed in your PC, it’s orga-
nized much like what Maximum PC Senior Editor Gordon
Mah Ung calls a “big-ass spreadsheet” with rows and col-
umns of data. However, to understand the process of access-
ing memory, a second analogy is useful.
Imagine RAM locations as books in a very elegant library
that uses a ladder attached to the top of the shelves for
access. The process of getting a particular book in such a
library works like this:1. Locate the book.
2. Roll the ladder to the correct set of
shelves.
3. Go up the ladder to get the book or
books off the shelf.
4. Put away any books that go on the
shelf.
5. Go down the ladder with the book(s).
6. Give the book(s) to the reader.
Just as the process of retrieving or returning a book
involves delays in moving from one set of shelves to
another (rolling the ladder) and then reaching the correct
shelf containing the book (going up and down the ladder),
RAM access is delayed by moving from one row of memoryFinally, the tireless
librarian delivers the
correct volume to its
recipient (3). All three
steps take time—that’s
why faster RAM (with
its faster librarian)
results in better
performance.
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