RAM and Virtual Memory Usage

[Guest]

My XP system works great, especially now that I've doubled my RAM to 512 MB.
However, the page file (virtual memory) usage is still well over 100 MB while
my RAM availability is over 300MB! Why? Why use the hard disk for memory
when so much RAM is available. This is normal (I think) in XP systems, but
is there a reason? Should I tweak something to make more efficient use of my
RAM? Thanks.

 

[Rock]

My XP system works great, especially now that I've doubled my RAM to 512
MB.
However, the page file (virtual memory) usage is still well over 100 MB
while
my RAM availability is over 300MB! Why? Why use the hard disk for memory
when so much RAM is available. This is normal (I think) in XP systems,
but
is there a reason? Should I tweak something to make more efficient use of
my
RAM? Thanks.

The page file is an integral part of XP's memory management. As the amount
of installed RAM goes up, the use of the page file goes down, assuming no
change in installed applications. Not all that you see in task manager is
actually page file usage. It includes space for items that might get
written to the page file but are not. To get an idea of how much the page
file is actually used, and to get a better understanding of Virtual Memory
in XP and the page file, read the article by the late Alex Nichol, MVP. In
it is a link to a utility by MVP Bill James and a modification of that by
MVP Doug Knox which will tell you how much the page file is actually being
used.

Virtual Memory in Windows XP
http://aumha.org/win5/a/xpvm.htm

 

[AJR]

As Rock alluded - virtual memory is used regardless of the amount of
installed memory.

 

[Ron Martell]

My XP system works great, especially now that I've doubled my RAM to 512 MB.
However, the page file (virtual memory) usage is still well over 100 MB while
my RAM availability is over 300MB! Why? Why use the hard disk for memory
when so much RAM is available. This is normal (I think) in XP systems, but
is there a reason? Should I tweak something to make more efficient use of my
RAM? Thanks.

Most of what you see reported as PF Usage will actually be "phantom"
usage that does not represent actual valid memory content that has
been relocated from RAM to the page file.

Instead, most of what you see with your present configuration will be
the result of the unused portions of memory allocation requests. By
design pretty much everything that runs on the computer, including
Windows components, device drivers, and application programs, will ask
for memory allocations that are larger than what they usually need
under normal circumstances. And again by design Windows must allocate
memory address space to satisfy all of these requests. What Windows
does is to allocate RAM only to those portions of the requests that
are actually used, and to use space in the page file for the unused
portions. Note that this mapping of unused memory requests to the
page file does not require any actual disk activity - all that is
needed are entries in the memory mapping tables maintained by the CPU.

For example, on my own machine at this moment PF Usage is reported as
607 mb. However, the Bill James utility that is referenced in the
Alex Nichol article that Rock referred you to shows that there is only
71 mb of valid memory content in the page file. The rest (536 mb) is
phantom usage as I have described above. This is on a system with 1
gb of RAM and 6 applications open on the task bar plus antivirus,
antispyware, and a backup utility running.

Hope this explains the situation. Good luck
Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca
Syberfix Remote Computer Repair

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."

 

[Guest]

The page file is an integral part of XP's memory management. As the amount
of installed RAM goes up, the use of the page file goes down, assuming no
change in installed applications. Not all that you see in task manager is
actually page file usage. ETC......................

Outstanding info. The link you provided also was great reading. Now I know
it all regarding RAM and virtual memory! Thanks to you both.
EW

 

[Rock]

Outstanding info. The link you provided also was great reading. Now I
know
it all regarding RAM and virtual memory! Thanks to you both.

You're more than welcome. Enjoy.

 

[Guest]

Most of what you see reported as PF Usage will actually be "phantom"
usage that does not represent actual valid memory content that has
been relocated from RAM to the page file.

ETC..........

Thanks, Ron. More good info. I've often wondered about the necessity of
adding more RAM when I saw "unused" RAM with a substantial swap file. But I
get it now.

EW