Website Quote:
http://computer.howstuffworks.com/question175.htm
Will Adding more RAM makes my computer run
Faster?
Up to a point, adding RAM (random access memory) will normally
cause your computer to feel faster on certain types of operations.
RAM is important because of an operating system component called
the virtual memory manager (VMM).
When you run a program such as a word processor or an Internet
browser, the microprocessor in your computer pulls the executable
file off the hard disk and loads it into RAM. In the case of a big
program like Microsoft Word or Excel, the EXE consumes about 5
megabytes. The microprocessor also pulls in a number of shared DLLs
(dynamic link libraries) -- shared pieces of code used by multiple
applications. The DLLs might total 20 or 30 megabytes. Then the
microprocessor loads in the data files you want to look at, which
might total several megabytes if you are looking at several
documents or browsing a page with a lot of graphics. So a normal
application needs between 10 and 30 megabytes of RAM space to run.
On my machine, at any given time I might have the following
applications running:
* A word processor
* A spreadsheet
* A DOS prompt
* An e-mail program
* A drawing program
* Three or four browser windows
* A fax program
* A Telnet session
Besides all of those applications, the operating system itself is
taking up a good bit of space. Those programs together might need
100 to 150 megabytes of RAM, but my computer only has 64 megabytes
of RAM installed.
The extra space is created by the virtual memory manager. The VMM
looks at RAM and finds sections of RAM that are not currently
needed. It puts these sections of RAM in a place called the swap
file on the hard disk. For example, even though I have my e-mail
program open, I haven't looked at e-mail in the last 45 minutes. So
the VMM moves all of the bytes making up the e-mail program's EXE,
DLLs and data out to the hard disk. That is called swapping out the
program. The next time I click on the e-mail program, the VMM will
swap in all of its bytes from the hard disk, and probably swap
something else out in the process. Because the hard disk is slow
relative to RAM, the act of swapping things in and out causes a
noticeable delay.
If you have a very small amount of RAM (say, 16 megabytes), then
the VMM is always swapping things in and out to get anything done.
In that case, your computer feels like it is crawling. As you add
more RAM, you get to a point where you only notice the swapping
when you load a new program or change windows. If you were to put
256 megabytes of RAM in your computer, the VMM would have plenty of
room and you would never see it swapping anything. That is as fast
as things get. If you then added more RAM, it would have no
effect.
Some applications (things like Photoshop, many compilers, most film
editing and animation packages) need tons of RAM to do their job.
If you run them on a machine with too little RAM, they swap
constantly and run very slowly. You can get a huge speed boost by
adding enough RAM to eliminate the swapping. Programs like these
may run 10 to 50 times faster once they have enough RAM!
I have seen this custom made computer
with 32Gb of RAM and 160GB of Harddisk. After the PC boot, you can
choose an application to run. This application will be taken out of
the harddisk completely and put into RAM. This method will speed up
the running of the application by 3 to 4 times! With a normal
Pantium 4 chip, this PC can juggle cutting-edge graphics games,
video playback, and applications like Autocad all at once, each
running perfectly and smoothly.[/b]
