Where Is My Memory Usage?

[shanenin]

I am working on an XP machine with very high memory usage. According to the task manager, there are just 37 processes running, those processes add up to about 170mb. according to the performance tab it is using over 500mbs. That leaves a difference of 330 mbs unaccounted for. I would like to reduce the total memory usage, but am not sure where to start looking.

[Pete_C]

I am working on an XP machine with very high memory usage. According to the task manager, there are just 37 processes running, those processes add up to about 170mb. according to the performance tab it is using over 500mbs. That leaves a difference of 330 mbs unaccounted for. I would like to reduce the total memory usage, but am not sure where to start looking.

First off, it is better to add more RAM than to reduce memory usage.

XP has a very powerful memory manager; I think the easiest way to visualize it is to think that it treats RAM and SWAP file as two portions of the same thing, memory ; one being fast and one slow.

The reality is that the XP memory manager lets each program think that it has a total of 4GB of memory addresses and can have any addresses it likes . Then it takes these "virtual" memory addresses and remaps them on the fly to real addresses. This way two applications , hardware or software , can think that they are being assigned the same preferred address , even though they are not. It also simplifies the restrictions on the coding which programmers must follow.

Finally it gets rid of the old restrictions in DOS based OS which had "system resources" where you had one 64KB page of memory on which all forms of input (user resources) were listed and the associated memory addresses, and another (graphic resources) was for output. If one got filled, you ran out of resources and crashed.

The danger if you use one of these RAM freeing programs is that it is overriding what the windows memory manager has done. It is not only second guessing its allocation, but it is adding one more layer or re mapping so that things will by necessity be slower at some point.

In task manager, select process tab. Then go to view on the toolbar at top, and click "select colums"

Make sure you have Mem Usage, and VM size checked also Peak mem usage . There are other things you can check out (Meme delta is the change in mem usage, page pool, non paged pool).

See it soon becomes confusing.

The performance tab adds another layer , physical memory, page file, kernel memory., commit charge .. ahh it just gets harder and harder.

So my guess is that you are seeing the RAM usage and total memory usage and they do not add up, because one is just ram , and the other is the combined use of ram and page file

[shanenin]

Normally one of the first things I do when diagnosing a computer running slow is to open the task manager and look at the PF Usage reading. If this number is higher then installed physical memory, I assume the computer is using the pagefile instead of real memory and slowing down alot.

For a benchmark, when I do a new load of XP sp2, the PF Usage reading is about 150mb. This is before installing any programs. For another benchmark, most client computers which have an old install of XP, after disabling all startups via msconfig, the PF Usage reading is about 200mb. This current computer I am working on seems odd. After disabling all startup programs the PF Usage reading is about 400mbs.

[TheTerrorist_75]

My PF Usage stays at a flat 288M with 25 processes and a trimmed down Startup. Most of that usage I trace to the anti-virus/firewall/heuristic scanner. I have 768MB of RAM.

[jcl]

Normally one of the first things I do when diagnosing a computer running slow is to open the task manager and look at the PF Usage reading. If this number is higher then installed physical memory, I assume the computer is using the pagefile instead of real memory and slowing down alot.

PF Usage is the maximum amount of pagefile space that could potentially be used. I don't know where you can find the amount of space actually used.

Edited July 22, 2007 by jcl

[shanenin]

I kind of figured that was not actual memory used, but it seemed to be a ballpark estimate of really memory being used.

[jcl]

I kind of figured that was not actual memory used, but it seemed to be a ballpark estimate of really memory being used.

Memory Usage, Memory Usage Delta, and Page Fault Delta are probably more useful.

(I'm not sure if anything in the Performance tab is useful. Available Physical Memory, maybe. Task Manager is baffling.)