Memory Usage vs. Physical Memory.Available

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Guest

When running an application, I observe some changes in Memory that I don't completely understand
I used the native Windows Task Manager to get the following statistics

I have 1GB of RAM on my machine

As soon as the application is executed, both "VM Size" (virtual memory) and "Mem Usage" (on the Processes tab) , for the application's process, begin to increase in a one-to-one manner (i.e. if VM Size = 10,000K, "Mem Usage" = 10,150K).

This behavior continues until reaching approximately 900,000K (almost 1 GB). When it reaches this point, "Mem Usage" drops significantly to approx. 30,000K. My understanding of the reason for this drop is that when RAM is almost full, it will swap out to the Page file (Virtual Memory). Is this correct

When this drops off, "VM Size" continues to grow

When I see the "Mem Usage" drop off so dramatically, I am assume the application is freeing RAM
If this were the case though, I think the "available" Physical Memory on the Performance Tab would increase in proportion to the decrease, thus showing the RAM was truly freed
This is not occurring though. The "available" Physical Memory is not showing any increase at all

What is happening with the RAM in this situation & Why
I would like to get a firm understanding of this

Thank you
J.S.
 
J. S. said:
When running an application, I observe some changes in Memory that I don't completely understand.
I used the native Windows Task Manager to get the following statistics.

I have 1GB of RAM on my machine.

As soon as the application is executed, both "VM Size" (virtual memory) and "Mem Usage" (on the Processes tab) , for the application's process, begin to increase in a one-to-one manner (i.e. if VM Size = 10,000K, "Mem Usage" = 10,150K).

This behavior continues until reaching approximately 900,000K (almost 1 GB). When it reaches this point, "Mem Usage" drops significantly to approx. 30,000K. My understanding of the reason for this drop is that when RAM is almost full, it will swap out to the Page file (Virtual Memory). Is this correct?

When this drops off, "VM Size" continues to grow.

When I see the "Mem Usage" drop off so dramatically, I am assume the application is freeing RAM.
If this were the case though, I think the "available" Physical Memory on the Performance Tab would increase in proportion to the decrease, thus showing the RAM was truly freed.
This is not occurring though. The "available" Physical Memory is not showing any increase at all.

What is happening with the RAM in this situation & Why?
I would like to get a firm understanding of this.

Thank you!
J.S.
Click to expand...

See MVP Alex Nichol's article on Memory Management in Windows XP at
http://aumha.org/win5/a/xpvm.htm

If you have further questions please post them back here.

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."
 
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