virtual memory paging file size less than system ram amount?

[JoeyPruett]

allo!

on a couple of our servers and desktops, i've noticed that the virtual
memory paging file size is actually set at less than the installed
system ram. for example, we have a 16GB RAM server and the paging file
size is at 4GB. does this negatively affect performance?

thanks,

-J

 

[Jim]

allo!

on a couple of our servers and desktops, i've noticed that the virtual
memory paging file size is actually set at less than the installed
system ram. for example, we have a 16GB RAM server and the paging file
size is at 4GB. does this negatively affect performance?

thanks,

-J

Interesting question. The answer is "not necessarily".
Jim

 

[JoeyPruett]

that's kind of what i was thinking. it doesn't seem to be affecting
performance as far as i can tell. but, i'm guessing there may be some
instances where it could cause problems.

i'm assuming windows will use physical ram first, then the page file,
then performance may suffer if the page file is too small.

oversimplified, but on the right track?

-joey

 

[Ken Blake, MVP]

that's kind of what i was thinking. it doesn't seem to be affecting
performance as far as i can tell. but, i'm guessing there may be some
instances where it could cause problems.

i'm assuming windows will use physical ram first, then the page file,

Yes.



then performance may suffer if the page file is too small.

No. Performance starts to suffer as soon as you use the page file. If you
need more memory than is available (total: RAM + page file), performance
doesn't suffer; you just can't run any more applications.

Having the page file size (at least the starting size) smaller than the
amount of RAM is no problem at all. In fact, it's usually best to leave the
starting size small but permit it o expand as needed. For more inforamtion,
read this article by the late MVP, Alex Nichol, "Virtual Memory in Windows
XP," at http://aumha.org/win5/a/xpvm.htm

 

[Ron Martell]

allo!

on a couple of our servers and desktops, i've noticed that the virtual
memory paging file size is actually set at less than the installed
system ram. for example, we have a 16GB RAM server and the paging file
size is at 4GB. does this negatively affect performance?

Not necessarily.

The relationship between pagefile size and memory size is something
that originates with Unix/Linux and should remain there.

Windows uses the pagefile to compensate for the *lack* of sufficient
physical RAM to satisfy the total memory requirements of the computer.
Therefore the relationship between pagefile and RAM is an inverse one
- more RAM means less pagefile and less pagefile means more RAM,
provided all other factors are held constant.

Caveat: There is one circumstance where there is a direct
relationship between RAM amount and pagefile size and that is in
regards to the "system failure memory dump" If you want to use the
"full memory dump" option for this then the pagefile size must be at
least equal to the amount of RAM because Windows XP uses the pagefile
on the boot drive to receive the memory dump contents and then renames
the file when the dump is complete. This is not, however, a
performance issue.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

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

 

[JoeyPruett]

thanks all!