Memusage vs VM Size

[amol_pk]

I have a Windows XP running on P4 2.5Ghz CPU with 512 MB of RAM. I have been loooking at the task manager and have a few questions. From my understanding of VM, VM or Paging should be done only when the RAM gets full. But when I check the Task Manager on startup for every process I see a value under Mem Usage and VMSize. What does it mean ?? If I sum up the mem usage for every process it still is less than my 512 MB RAM. Is my understanding of VM Size here wrong ??

My next question how advisable is it and how to reduce the paging.

Any comments/advice highly welcome.

TIA, Amol.

[pgriffet]

Hi, take a look here : http://www.aumha.org/a/xpvm.htm

Excerpt :

Can the Virtual Memory be turned off on a really large machine?

Strictly speaking Virtual Memory is always in operation and cannot be "turned off." What is meant by such wording is "set the system to use no page file space at all."

Doing this would waste a lot of the RAM. The reason is that when programs ask for an allocation of Virtual memory space, they may ask for a great deal more than they ever actually bring into use - the total may easily run to hundreds of megabytes. These addresses have to be assigned to somewhere by the system. If there is a page file available, the system can assign them to it - if there is not, they have to be assigned to RAM, locking it out from any actual use.

Pierre.