What is memory anyway?
Memory is like short-term memory in the brain
analogy for computers. Before you can work
on a problem or idea, you need to get the
particulars into short term memory before
you can work on them. The hard drive is like
long-term memory.
Everything the computer is works
on has to
be in memory. Things it isn't
working on
can be stored on the hard drive.
Windows
itself is "loaded"
into memory.
When you start a program the
CPU loads it
into memory. When you press a
key on the
keyboard the CPU loads it into
memory. When
you "save" a document
the CPU "writes"
it to the hard drive, but it
remains in memory
too. The CPU is obviously the
component that
does the "thinking",
but just like
you, it can't do much until it
has the details
in memory.
If the CPU needs more room in memory than
you have installed, it shifts some of the
content it isn't using right at the moment
to "virtual memory". Virtual memory
is located in the "swap file" on
the hard drive. It's called swap because
Windows "swaps" memory contents
between physical memory and this virtual
memory.
For example, if you have two large programs
open and switch from one to the other, Windows
first swaps the one you were using out of
physical memory into virtual memory. Then
it brings the one you are now using out of
virtual memory and puts it in physical memory.
All this takes considerable time because
virtual memory (the swap file on the hard
drive) is much slower than physical memory.
More memory is good because it means there's
less swapping going on.
How much memory?
You'll improve the performance (speed) of your computer more by increasing
memory, say to to 256 MB, than by getting
a faster processor.
If you're buying a new computer look for
at least 256 MBytes of memory. If you want
higher performance, particularly with Windows
XP, be sure you get 512 MB of 266 MHz or
faster DDR SDRAM.
The keyword here is DDR (Double Data Rate).
512 MB is the size. 266 MHz is the data rate
-- twice that of ordinary SDRAM (Synchronous
Dynamic Random Access Memory.
Which memory to buy?
Thinking about adding memory to upgrade your
computer? Don't buy cheap memory -- it's
often the source of mysterious PC problems.
Try Crucial Technology for top tier memory at a good price. They're
the online arm of Micron -- a well-known producer. Their website
makes it easy to find the right memory for
your computer, or other devices like digital
cameras. If you're worried about installing
memory, check out these great instructions at Crucial. Samsung also makes quality memory.
Get a good price for Samsung memory at Newegg.com.
The "Memory Configurator" at Shopper.com is another way to locate
the memory you need. There are links on buying
and installing memory there too. Or try Kingston, who also sell good memory.
Installing memory
The hardest thing about installing memory
is getting it seated properly. In my computer,
just getting at it is a problem. In the case
of memory that pivots into place, it's not
easy to see exactly how to do it. Memory
that plugs in straight is often hard to seat,
and if you don't get it started right, you
can break the socket trying to force it in.
Check out these great instructions from Crucial Technology for installing memory.
If you've never done it before
you may want
to get someone who has to help,
or get it
done at a shop.
Before you start to install new memory, before
you even open your new memory package, read
the ESD precautions on the upgrade page.
Resources
See Rob Williams' Computer Memory Upgrade guide. This is a very complete reference. |