Virtual Memory

[Virtual Memory]

Hi,

I've got a couple of questions for you guys for which I
couldn't find any answers on the Web.

I'm using Windows XP Pro. I want the best performance I
can get out of my system (I'm a developper using .NET and
SQL Server locally frequently and together). So, I
bought lots of RAM and set the Virtual Memory size option
to 'No Paging File'.

Basically, my system seems to run a lot smoother since I
did this. Now, if I use Task Manager to look at my
running processes and add-up the amount of memory they
use, it doesn't come close to the amount specified in the
performance tab. In fact, it's much lower. I looked it
up and learned that the total amount of memory used is
calculated by adding the amount of RAM and the amount of
Virtual Memory used by all running processes. Since I'm
not supposed to be using any Virtual Memory, as per my
setting, I didn't know where the missing MBs of RAM were!

After tunning my Task Manager a little bit, I discovered
that I could add columns of info to the 'Processes' tab.
I added the 'VM Size' column, which I thought should be 0
for all my processes, and to my surprise a lot of memory
was assigned as VM!!!

Now, before I continue, let me just say that my total
amount of available memory is the amount of RAM I have in
the system. Basically, this seems to indicate that the
system really is not using any Virtual Memory at all!

So, my question is why is there memory assigned as VM in
task manager even though I am not using any?

A second question would probably be is it a good idea not
to use a paging file? Even with lots of RAM memory, a
lot of paging/swapping was taking place and it was
slowing my system down. That's why I shut it off.

Thanks a lot,

Skip.

 

[Ron Martell]

Hi,

I've got a couple of questions for you guys for which I
couldn't find any answers on the Web.

I'm using Windows XP Pro. I want the best performance I
can get out of my system (I'm a developper using .NET and
SQL Server locally frequently and together). So, I
bought lots of RAM and set the Virtual Memory size option
to 'No Paging File'.

Basically, my system seems to run a lot smoother since I
did this. Now, if I use Task Manager to look at my
running processes and add-up the amount of memory they
use, it doesn't come close to the amount specified in the
performance tab. In fact, it's much lower. I looked it
up and learned that the total amount of memory used is
calculated by adding the amount of RAM and the amount of
Virtual Memory used by all running processes. Since I'm
not supposed to be using any Virtual Memory, as per my
setting, I didn't know where the missing MBs of RAM were!

After tunning my Task Manager a little bit, I discovered
that I could add columns of info to the 'Processes' tab.
I added the 'VM Size' column, which I thought should be 0
for all my processes, and to my surprise a lot of memory
was assigned as VM!!!

Now, before I continue, let me just say that my total
amount of available memory is the amount of RAM I have in
the system. Basically, this seems to indicate that the
system really is not using any Virtual Memory at all!

So, my question is why is there memory assigned as VM in
task manager even though I am not using any?

A second question would probably be is it a good idea not
to use a paging file? Even with lots of RAM memory, a
lot of paging/swapping was taking place and it was
slowing my system down. That's why I shut it off.

Thanks a lot,

Skip.

Technically the term Virtual Memory in Windows XP refers to the
combined total of the physical RAM and the paging file. With no
paging file your virtual memory should therefore be the same as your
RAM.

Does the file pagefile.sys actually exist on your hard drive? If so,
can you delete it? If it exists and cannot be deleted then Windows
is ignoring your "no page file" setting and has created one.

I would question that Windows was actually using the paging file so
long as there was available RAM. By using I mean the actual moving of
active memory content from RAM to the paging file. What it was doing,
and what it should do so as to allow you to make the most efficient
use of your available RAM, is to use that RAM only for those portions
of memory requests that are actually being used and using the space in
the paging file to satisfy the memory address requirements of the
unused portions of these requests.

Memory allocation requests from Windows components, device drives, and
application programs are generally overstated and sometimes quite
substantially so. With no paging file Windows has no choice but to
allocate RAM addresses even to the unused portions of these requests.

I am surprised that you feel that your system is actually faster with
the paging file eliminated. Have you done any timed benchmark tests
both with and without the paging file to verify your impression?

Hope this is of some assistance.

Good luck


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

"The reason computer chips are so small is computers don't eat much."