Physical Memory, Commit Charge, Kernel Memory 2

[Mstr1mir]

Hello everyone,

I have this snapshot of my PC task manager. I would like some analysis about it. whether the RAM memory in my PC adequate or not.

there are four boxes in the snapshot

1. Physical Memory.
2. Commit Charge.
3. Kernel Memory
4. Total.

each one of these has subtitles.

I would like to get demonstration about these four headlines.

Regards

 

[Nelviticus]

Wikipedia has detailed explanations of what they all mean:
Commit charge
Kernel memory
Physical memory

The answer to your question is pretty complicated, but if you want to know whether your PC has enough memory you don't need to understand all those figures.

How much you need depends on what version of Windows you run and what you do with your PC. I'd say that if you run Windows XP and do a bit of gaming, web browsing and document editing then 1GB would be enough, but 2GB would be better!

Regards

Nelviticus

 

[goombawaho]

I'd like to give a different memory number for Windows XP. Most PCs that do "normal things" - web browsing, e-mail, Office software, do just fine with 512MB/768MB.

Sure, it would be nice if everyone had 1GB of memory, but remember that when XP came out, 1GB of RAM was like phenomenal. So we're looking at XP in today's eyes and not when it came out and it's requirements back then.

I don't see too much of an improvement between 1GB & 2GB vs. going from 512MB to 1GB, so I'd target the 768MB/1GB number for NORMAL activities.

If you do CAD design or heavy duty applications, then sure - pile on the RAM.

 

[Mstr1mir]

thanks,

however, I want to understand the meaning of physical memory, Kernel Memory, and Commit Charge, Total

all these if we understand them then we can evaluate any PC regardless the operating system.

so anyone can explain the snapshot with very details?

I mean look at the physical memory in the snapshot

the total is 502 MB
the available is 209 MB
the system catche 312 MB

look at the available physical memory, this tells us we have less than the half of the total memory which is not healthy for the PC. but i didnt understand the system catche. also, I have 512 MB but it is shown in the total physical memory that i have 502 MB. where the 10 MB gone ?

so my idea is if we go over each section of this snapshot, we can learn something even if it's complicated at least we understand it conceptually.

Looking forward from everyone to participate.

Regards

 

[kmcferrin]

What you're asking ("Do I have enough RAM?") can't be easily answered from the info provided. One thing tha tyou can do with what you provided is to look at Total and Peak Commit Charge and compare to Total Physical memory.

If Peak Commit Charge is greater than your physical memory, then at some point since boot you're using more memory than you have installed in your PC. But the screen you're showing us doesn't tell us if that was a one-time thing or a regular occurrance, so that's relatively useless information.

If Total Commit Charge is great than your physical memory, then at that exact moment you are using more memory than you have installed. But again, it doesn't tell us if it's a one time thing or a regular occurrance, so as above, it's not particularly helpful.

If you want to really know if a system has enough RAM, you must use perfmon and monitor the following counters:

Memory\Available MBytes (or KBytes or Bytes, depending on which you prefer)
Memory\Pages/sec

There are others that you might watch for page file usage, disk queue length, etc, but generally the two listed above are the most important ones.

Otherwise Nelviticus posted links to good explanations of what the screenshot you posted means.

________________________________________
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MCITP:Enterprise Administrator

 

[Glenn9999]

The help that is given for that screen in the Task Manager is sufficient to explain it all, and there's really not much that you can control in most of those numbers, either.

The question is more what you are trying to know from looking at this screen, and as kmcferrin pointed out, whether there are better methods to obtain this information.

As for physical memory, you seem to come from a DOS related understanding on that figure - what has been specified in your screen shot is an acceptable situation in and of itself. Besides, with how Windows handles memory, that situation is very fluid anyway, depending on the programs you run and how they handle memory allocation. Again, kmcferrin points this out - a specific snapshot in time has no meaning with Windows.

HTH but I'm not sure that's what you're looking for.

Measurement is not management.

 

[Mstr1mir]

well,

I exactly want to say whether that PC is having low memory or not.

and if it has low memory, how can u prove that logically.
and if its memory is OK, then how can you prove that from the snapshot

the operating system is Win XP PRofessional
the main software is running in the operating system is SQL Server 2005 upgraded to SQL 2008.
Plus Microsoft Package.

----------

moreover, the total physical memory is 502 MB demonstrated in the snapshot, but we have to have 512 MB. where did the 10 MB go ?


Regards

 

[cdogg]

Again, the snapshot is not enough information for you to draw a concrete conclusion from. You can analyze the data and come up with some ideas, but to reach a decision on upgrading memory, you have to make assumptions about the data shown in the snapshot. kmcferrin pointed out examples of this above.

Now earlier in this thread you said:
"[blue]this tells us we have less than the half of the total memory which is not healthy for the PC[/blue]"

Having less than half of the memory available isn't necessarily unhealthy. In fact, some of the memory in use is actually "paged" meaning it's reserved for future use by an application or the kernel. So although your snapshot shows a certain amount available and in use, the numbers don't tell the whole story. A good example is if you were to reduce the system RAM to 256MB on that same computer. The same snapshot might show something like 75MB available, a difference of about 125MB when you reduced the RAM by 256MB. As you see depending on the amount installed, the environment will react differently to the amount that's kept in reserve.

You really need to poll data from a series of other tests and benchmarks, then compare the results against other computers that have more memory but the same hardware/software. That is the only true way of knowing if more memory is actually needed. I can tell you that depending on the age of the system, memory in general is pretty cheap now. So bumping up the computers in your environment to at least 1GB shouldn't cost much.

the total physical memory is 502 MB...but we have 512 MB. where did the 10 MB go?

We have a lot of HP desktops where I work that are in the same situation. The integrated GPU on the motherboard reserves 10MB of the system RAM for video at startup. It also has its own dedicated memory too, so I'm not sure why it really needs that. But if you were to install a video card, you would see that total reported normally as 512MB. Then again on the flipside, most business desktops don't need strong 3D performance or a lot of video memory. So adding a card can be overkill.


If you want better answers from this point on, please describe to us more about your environment (number of workstations, their age, etc.), the situation you're facing (are you being pressured by management or another dept within your company), or other details that you think would help us visualize the problem.

~cdogg
"Insanity: doing the same thing over and over again and expecting different results." - Einstein
[tab][navy]For posting policies, click [/navy]here.

 

[goombawaho]

Okay - let's just get 2GB of RAM and put it in the machine and that should cover everything.

 

[Glenn9999]

I exactly want to say whether that PC is having low memory or not.

Here's your answer.

If you want to really know if a system has enough RAM, you must use perfmon and monitor the following counters:

Memory\Available MBytes (or KBytes or Bytes, depending on which you prefer)
Memory\Pages/sec

The second value is vastly more important for your question (though the first is interesting to monitor), since it measures the number of times that Windows touches the page file. That is a feature of Windows from about the days of DOS - virtual memory. In essence, to use a page file on disk to simulate an increased amount of memory. No matter the amount of physical RAM installed (*), Windows will generally allow a full 2GB of memory access.

In other words, if you run something that has sufficient memory, it will show very little page file access (not none - that's how Windows works, it touches the page file first until its proven that the allocated memory can be fully handled in physical RAM upon processing).

But if you run something that requires more than the free physical RAM, it will start swapping out other things that are in memory and start using that memory, and even swapping pages of memory to and from the page file. In this case, the Pages/sec figure will go up, often considerably. This indicates that there is not enough physical RAM for the applications in question to run. If you even push the 2GB level on most machines, you can really tie up the machine and make it slow, even after the fact.

So basically, what you do is fire up perfmon, set those two values, and then start running a few applications on the system in a normal fashion and then see what happens.

and if its memory is OK, then how can you prove that from the snapshot

You don't from the performance tab of Task Manager. That's what we've been telling you.

(*) - excepting the /3GB switch where supported.

Measurement is not management.

 

[Mstr1mir]

ok,

The integrated GPU on the motherboard that reserves 10MB of the system RAM for virtual memory. this is really useful answer. really thanks

well, there are 24 workstation connected to a domain controller server. for each workstation, there is SQL 2005 upgraded to 2008.

I want to make sure if I can install more softwares to those workstation without a threat of low in memory.

so, by looking at that snapshot, I thought I would be able to determine if the memory suites for later software installation or not.



lemme clarify somethin that I understood after posting this thread.

if u see the snapshot, it actually tells u everything you wanna know.

first of all, the physical memory that divided to 2 parts.

The available Physical memory, and the Catche memory

adding up the two parts yeild the total physical memory.

in the snapshot, the system catche memory is 312 MB that is being used by the operating system plus the 10 MB that u told me the GPU reserves it for the virtual memory.

now look at the available physical memory. you will find that it's 209 MB

then the total physical memory that we will have 512 MB as we suppose to have.

now, another issue that is really vital, the paging files is sould be 1.5 times the total physical memory.
so, for all the workstations, the page files is approximately changeable between 400 - 450 MB / 870 MB.


Regards

 

[Glenn9999]

Nothing more to be said about the issue of memory allocation, so I'll go onto the page file question:

now, another issue that is really vital, the paging files is sould be 1.5 times the total physical memory.
so, for all the workstations, the page files is approximately changeable between 400 - 450 MB / 870 MB.

This is just an old saw that gets passed around ("the page file should be 1.5x physical memory"). I don't really know where it got started, but it's completely invalid for Windows XP (and Vista and 7, too). But the Task Manager indeed does seem to show what you need to know. The commit charge is not the amount of page file on disk, but the amount of it utilized.

It's saying that
1) You are actually using about 450712KB of the page file.
2) It peaked out at about 885272KB in the time that the system has been online (since you first turned it on).
3) You have 1258280KB actually allocated on disk for the page file.

Now, when you exceed the "limit" value, Windows will automatically expand the page file to account for the new allocation (and will produce a message to this effect in the taskbar). This means that you aren't setting anything concrete for the system (again one of those numbers you don't have much control over that I mentioned). Now I can set this page file to a very low number (almost approaching zero), but Windows will always expand it to allow for the virtual memory that is allocated. This expansion will produce performance issues due to the processing involved to do this - as well the page file could potentially be fragmented on the disk.

For the paging file, you would do best to:
1) Allocate it for a size that the system will never likely reach. Or even better, just allocate it so Windows will manage it. Again, perfmon and the appropriate value (Paging File/Peak % or some such thing) will be useful to watch as you use the computer normally.
2) The better part is to make sure the paging file is not fragmented ([link "

http://technet.microsoft.com/en-us/sysinternals/bb897426.aspx"

]PageDefrag[/url] can be useful for this purpose.)
and if you can put it closer to the front of your fastest drive.

HTH.

Measurement is not management.

 

[Freestone]

Glen9999 the 1.5 time physical memory has been recommended by Microsoft for as long as I remember...here is just one example of it:

http://support.microsoft.com/kb/308417

 

[Glenn9999]

When you leave it to Windows itself, though, I can't observe that they're following their own rules - like I said, I don't know where that comes from and it definitely doesn't make any sense to do it from my actual observations. For example, the actual allocation for my computer is as the OP's above. 1250MB for 512MB memory, which is 2.4x physical memory by my account. Now I've observed that Windows will expand the page file to 768MB (1.5x) if I were to allocate NO space to it, which might be where that is coming from - but I wouldn't suggest doing that for obvious reasons that were enumerated in my last post.

It may have applied once upon a time to Windows (I heard it more consistently with the 9x series), but I observe it doesn't seem to have any correlation or sense to what I've seen in XP or anything past it (I know the virtual memory handling is different there, as well). It wouldn't surprise me that what you are seeing is something that is deprecated that just keeps getting carried over in documentation from version to version.

I would think one would do better to use the monitoring tools that XP has now.

Measurement is not management.

 

[BadBigBen]

Glenn, I got to agree that now a days, it is best to leave the PageFile alone and handled by the OS...

Freestone and Glenn, if you read that KB, then you should notice that it says, MINIMUM is 1.5x and MAXIMUM 3x on one drive, and on two or more drives 1.5x on EACH...

I hope this settles that...



Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

How to ask a question, when posting them to a professional forum.

 

[kmcferrin]

And that guideline makes some sense, when you're dealing with smaller amounts of memory. But if your PC has 4GB of RAM, it's a bit silly to have a page file that runs from 6GB to 12GB. I just let Windows manage it in most cases.

________________________________________
CompTIA A+, Network+, Server+, Security+
MCTS:Hyper-V
MCTS:System Center Virtual Machine Manager
MCSE:Security 2003
MCITP:Enterprise Administrator

 

[Glenn9999]

Indeed. Even with a system that has 512MB memory like mine, it doesn't seem to make too much sense - of course this is as explained in the talk about Physical Memory in this thread. The more physical memory in the machine, the smaller the swap file that you would need - to the point that it would be a inverse relationship after a certain point (like I said the 9x series and 2000/XP seem to be using different virtual memory schemes - XP being much better).

I started monitoring my swap file after my first post on the page file topic and noticed it running around 150MB normally and peaking at 350MB when I really made a point to start loading everything I could think of on the system. I tried to set it there but Windows still insisted on a page file size of 1250MB - even when it seems that I could upgrade the machine to 1GB and seemingly run the system with NO page file at all.

The higher requirements listed in the OP's post is likely due to the SQL oriented software being resident, but is still not in line with the 1.5x rule that's been thrown about. The best these days, seems to just be sure the page file is on the fastest drive and the file itself is not fragmented.

Measurement is not management.

 

[BadBigBen]

The best these days, seems to just be sure the page file is on the fastest drive and the file itself is not fragmented.

I've found that from normal use, e.g. Office, surfing the web, the page file is not needed with 1GB+... but it definately is needed if you use almost any Adobe, CAD, and some other softwares still need it, at a respectable size or they do funny things...

Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

How to ask a question, when posting them to a professional forum.

 

[Freestone]

I was just using the article as an example to Glenn to show that the "old saw" originated from Microsoft itself. I didn't mean to imply I agreed with the recommendations. At least it generated even more interesting posts

 

[kmcferrin]

Here's a good example. I run Vista x64 and have 4GB of RAM installed on my PC. At the moment I have Firefox open with 8 tabs on my login session, my wife is logged in under her session with who knows what running, I have Outlook open, and I loaded Lord of the Rings Online (MMOG) and played for about 20 minutes. In the background I had Reliability and Performance Monitor running, capturing the "Page File\% Usage" and "Page File\% Usage Peak" counters. Both show zero for the min, max, and average for that period of time. So if Windows doesn't need it, it won't use it.

I let Windows manage my page file. But if I got into the page file details, the minimum allowed is 16 MB. That's right, 16 megabytes. The recommended size is 6139 MB, roughly 1.5x the amount of installed RAM. The currently allocated size is 4393 MB, of which I routinely use zero.

________________________________________
CompTIA A+, Network+, Server+, Security+
MCTS:Hyper-V
MCTS:System Center Virtual Machine Manager
MCSE:Security 2003
MCITP:Enterprise Administrator