Virtual memory on systems with a lot of RAM

[Guest]

Hello.


I just recently bought two additionally RAM sticks and put all together into
my XP box. Now I have 2.5 gigs so I wonder is there any need for having
Virtual memory. My pc usage is mainly surrounded by basic things (Word,
Outlook, Adobe Reader, WMP, …) plus some testing in Virtual Server 2005 R2.

Would I need VM anyway since I never go over 2 gigs?


Miha

 

[R. McCarty]

Yes, It's a misconception that disabling the Pagefile is beneficial.
In fact if you do disable it, XP will quietly create a temporary
one in C:\Windows\System32\TempPF.Sys regardless of your
settings in System Properties.

Programs are written to take advantage of Virtual Memory.

You can monitor Pagefile usage with a counter in Perfmon.Msc.
Even with heavy application loading you'll likely see only 50-100
Megabytes of traffic on the pagefile.

My desktop has 2.0 Gigabytes of RAM and my pagefile use is
currently at 21.2 Megabytes.

I'd suggest you read an article written by the late Alex Nichol, MVP:
http://aumha.org/win5/a/xpvm.htm

 

[Guest]

But I don't get this “To take advantageâ€. How can be using slow hard drive
advantage over using 1000x times faster RAM if having plenty of RAM?


Miha

 

[Gerry Cornell]

Miha

Read the Article by Alex Nicholl
http://aumha.org/win5/a/xpvm.htm

The Windows operating system needs to use virtual memory for some
operations. The memory dump when a Fatal Error occurs needs
approaching 50 mb. For most operations, however, RAM memory will be
used in preference to virtual memory. You need to understand that the
system grants allocations of virtual memory to a programme but this is
only used on a required basis. Most of the time it will not be used.
You can monitor actual usage of the pagefile using pagefilemon.

A small utility to monitor pagefile usage:
http://www.dougknox.com/xp/utils/xp_pagefilemon.htm

Graphics and camera related programmes will bump up pagefile usage
from a typical 50 mb to a much more significant figure. Editing using
an undo feature pushes up pagefile usage.

--

Hope this helps.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[Poprivet]

But I don't get this "To take advantage". How can be using slow hard
drive advantage over using 1000x times faster RAM if having plenty of
RAM?


Miha

This is a over-simplified, but ... RAM will hold most everything you need
that you're running. Being interpretive, XP will, when the time is not
otherwise used, make guesses at what else you might want to do and toss that
into virtual ram. That can even include apps related to the app you're
running, and which you've run and closed down. So, immediate-use things are
in RAM. "Maybe" use stuff gets flowed off into VM. Graphics and
especiallly video will fill your couple Gig RAM quickly so you'll see the
pagefile growing then if you were to watch it. I'm referring to the editors
here, not to the images themselves.
Things are constantly being swapped back and forth between RAM and
Virtual RAM as you change the things you do in a program and work on various
other things, and especially when you have multiple applications running all
at once is when you'll definitely see advantages.
The more RAM you have, the less (not nothing) you have in VM, so the
faster things can run. For normal processes, XP likes to have 512 to a Gig
of RAM, so you're in decent shape. Remember, there's a lot going on behind
the scenes in an os.

HTH
Pop`

 

[Ken Blake, MVP]

I just recently bought two additionally RAM sticks and put all
together into my XP box. Now I have 2.5 gigs so I wonder is there any
need for having Virtual memory. My pc usage is mainly surrounded by
basic things (Word, Outlook, Adobe Reader, WMP, .) plus some testing
in Virtual Server 2005 R2.

Would I need VM anyway since I never go over 2 gigs?

Yes. Do not disable the Page File. Windows preallocates memory to the Page
File in anticipation of possibly needing to use it. If you disable the Page
File, those allocations get made to real memory instead, and the result is
that you can never use that part of your RAM.

Over and above that significant disadvantage, there is no possible benefit
to disabling it. If it's not needed, it won't be used.

 

[GSV Three Minds in a Can]

Yes. Do not disable the Page File. Windows preallocates memory to the Page
File in anticipation of possibly needing to use it. If you disable the Page
File, those allocations get made to real memory instead, and the result is
that you can never use that part of your RAM.

Over and above that significant disadvantage, there is no possible benefit
to disabling it. If it's not needed, it won't be used.

IIRC XP needs at least 50MB of VM/pagefile/pick your own term in order
to produce a mini-dump if it goes t!t$-up. Not sure what disaster
ensures if it hasn't got any. Some apps (like older versions of
photoshop) also used to have kittens if there was no pagefile. As you
say Ken, just let Windoze handle it .. and make sure that you never
actually use it for actual paging, coz the resulting performance is
pitiful.