How to limit cache in XP

Discussion in 'Windows Desktop Systems' started by elkinm, Nov 24, 2002.

  1. elkinm

    elkinm Guest

    My system memory always gets used up and the system becomes more hungry for swapfile size but when I check processes in task maneger the total memory usage does not come close to my available I don't need to have many programs running.
    System cache in task manager reeds in the hundreds on megabytes which is far more then I want or probable need.
    Cacheman can specify max and min cache for 9x versions of windows. Is there any way to limit cache in Win XP or do something so that windows does not eat up my ram?

    Thanks
     
  2. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    xp will adjust the woking sets of all programs, according to the available ram

    this is exactly so you do not use the pagefile unless you need to

    in other words, the more ram you have, the more ram you will use, and in so, speed the respective features of the program.

    what you see the pagefile doing, is creating avalilable information, so that it is ready to immediatly release ram, if it so needs to do.

    what you are witnessing is not pagefile use, it's pagefile activity, and it in fact speeds the os

    contrary to what you might have been told, or led to believe in the past, the more ram you have the more ram you will use, and in so, obviously, the bigger the pagefile you need, not a smaller pagefile

    in other words, what you want to do, as far changing the management of memory in xp...this will in almost alll situations, slow you down
     
  3. elkinm

    elkinm Guest

    I had nearly no problems with 256 MB oram so when I got 256 more I was expecting it to always stay free and my system to speed up, instead the ram gets filled up very quickly and it spends ages going to the hard drive.
    That is why I want to limit cache so it keeps a nice balance and does not exeed it's limits.
    Also with 256 MB I ocationaly recieved a message saying that windows swap file is running low and it will enlarge it. Now I get this message continuously which tells me that something is very wrong if windows uses up 512 MB faster then 256.
     
  4. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    exactly what is your pagefile settings?

    as far as getting more ram, you expecting for the additional to remain free...no, xp will increase the working set as you increase your ram

    also, xp makes use of ram, however, is always prepared to immediatly release the respective ram.

    in other words, the amount of ram that is available for immediate use is much higher then the amount of ram that is being reproted as free.

    xp is so much better at manageing memory then 9x for just these reasons...what you are looking at might have been an issue in 9x, it is not an issue in xp.

    now, since you now have 512 of ram, make sure your pagefile is set with an initial minimum of no less the 1.5 of the ram...leave excpansion enabled to 4x ram, or the max, which should be 4096.

    my personal recomendation, if you are not short on disc space, is to double the ram for the initial miniumum, and leave expansion to what is left available, which is 4096
     
  5. elkinm

    elkinm Guest

    512 MB pagefile fixed and I am low on hard disk space with his much.

    It just does not make sence for everything to run slower with more ram. I belive that for some reason windows tries to put everything into ram and when needed makes a memory dump on the hard drive or things that need changing but with 256 MB id didn't have the ram so it did this normaly and gradualy making it faster without the long memory dumps or something.
    I never run anything that shoul fill up ram. With 256 I always have some free, but now any setious action and my ram is down to the tens and it takes a lot of time and a lot of hard drive noise for the system to work aggain.

    XP and NT should be configurable, there has to be a way to configure how it uses ram. I have seen max number of pages to alocate and other similar information but I don't know how that translates to real ram as I could not find the page size.
     
  6. yoyo

    yoyo _________________

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    Sorry, seems I didn't quite understand what you said about memory dumps. A memory dump is recorded when the system stops unexpectedly, in other words crashes. If it is a full or small dump depends on how you have configured it. Do you get memory dump messages? Are you sure your ram is installed properly?

    http://support.microsoft.com/default.aspx?scid=KB;en-us;q254649
     
  7. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    well, first of all, your pagefile is way too small....and it of course should never be fixed.

    I understand that you are losw on drive space, and that's one of your problems.

    understand this;

    it does not matter what size you set the pagefile, the os will actually page more, if the pagefile is too small, nto less.

    in other wprds, restrcting the size of the pagefile will not stop the disc usage, when it becomes neccessary, or limit it

    these are old notions that are definately counter productive in xp

    1) makeing the pagefile static is counterproductive..there is no user that will benenfit from this notion, and quite a few that will suffer performance...why would you dissable an activity, (expansion), that annot possibly happen until you want it to happen.(when the commit charge reaches the commit limit)...there is absolutely no reason to do this...it cannot possibly help any user.

    you, being short on disc space, should just let the os manage the pf, without even setting the initial minimum...in this fassion, the os will actually create a smaller pf then 1.5 when your discspace becomes rare, and in the mean time, it will resize it when the space is available, if and only if the commit charge reaches the commit limit.

    and second, if at all possible, you should not make the pagefile smaller then what microsoft says is the absolute minimum. this will obviously result in a performance variable if you do start to use close to all the ram you have installed

    the exact ms recomendation is the initial minimum no less then 1.5 obviously, iwith expansion enabled acording to microsoft

    if you insist creating a static pagefile, because of some missguided information you might have read...( such advise is often repeated nonsense), then you should have at least 3x ram to pexomate the minimum ms says is needed to be available....now, you are short on disc space, so this is not possible

    that's the first thiing

    the second thing is, of course, there is no way you should be running slower with more ram...I've never seen this happen, never heard of it...I'm suspecting some kind of ram issue...bad ram, incompatability, something

    if you are getting memory dumps, you should probably find the wayward program, or whatever is causing the memory dump, and address that issue...also, you can dissable memory dumps after you figure the cause, and you should dissable the dump if you don't plan on using the information to debug
     
  8. elkinm

    elkinm Guest

    With 256 MB averything was balanced, nut now the memory gets used up, probably by cache and very soon goes to nothing and then becomes useless. I am quite sure the ram is fine both the same Crucial.
    And I do indeed want to limit windows. I want it to use the memory needed, that I see for used programs, only some and little memory for cache. I just want to have controll and since windows can't handle the ram like I want to I need to control it.
    That is all I want complete controll.
     
  9. elkinm

    elkinm Guest

    Also, is there any way to determine exactly where all of the ram is going. The system cache and commit charge have to come from somewere? I want to track down all memory usage, maybee then I can control it.
     
  10. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    try perfmon...see if you can follow what's going on there

    I will say this again though, when you do controll the ram in the fassion that you believe you want, the os will be slower

    I can't give you anything further for what you've experienced, hopefully, someone else will have some information more usefull to you

    sorry
     
  11. Fungiver

    Fungiver Guest

    I'm confused. Pagefile(virtual memory) is a section of ROM that is used like RAM when your RAM is used up. Kinda like an open drawer in a filing cabinet. If your desktop(RAM) can't hold all the files then some are put in the open drawer. But if you have enough RAM turning pagefile off and forcing XP to keep everything in RAM results in system speed up. With a big enough desk(RAM) you don't need the fileing cabinet(pagefile) I have had mine turned off for over six months and along with increasing I\O pagelock limit, disabling executive paging,increasing highmem to 512MB and so on, my system flies. I would not recommend this method for anything less than 512MB of RAM. Unless you are a file server or are on a shared LAN you don't need pagefile with enough RAM.
     
  12. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    fungiver...you are misslead...your ideas concerning the pagefile are incorrect, and will slow you down

    first, since you seem to know what you are doing, you can do this to prove something to yourself;

    first, give yourself an adequate pagefile, say 2x ram

    reboot

    now, monitor page usage in permon

    now, eliminate your pagefile, reboot

    look to perfmon again...

    as you can see in perfmon, there is more pagining activity, not less when there is no psgefile.

    you nare slowing yourself down when you dissable the pagefile, or have one that is not adequate

    ...you cannot possibly stop xp from paging, and these attempts to do it actually cause more writting to disc, not less.

    please search for the "pagefile analogy" that I posted on this site, and you will have a better understanding of what the pagefile does, and where your ideas go awry.

    now, here's a paragrapgh from the microsoft mvp alex nichole;

    Windows will always try to find some use for all of RAM - even a trivial one. If nothing else it will retain code of programs in RAM after they exit, in case they are needed again. Anything left over will be used to cache further files - just in case they are needed. But these uses will be dropped instantly should some other use come along. Thus there should rarely be any significant amount of RAM ‘free’. That term is a misnomer - it ought to be ‘RAM for which Windows can currently find no possible use’. The adage is: ‘Free RAM is wasted RAM’. Programs that purport to ‘manage’ or ‘free up’ RAM are pandering to a delusion that only such ‘Free’ RAM is available for fresh uses. That is not true, and these programs often result in reduced performance and may result in run-away growth of the page file.

    end quote

    now, none of this optimization of ram is at all possible without a pagefile that the os will use efficiently

    this will clearly demonstrate the absolute need for a pagefile bigger then the ram that you have installed

    it does not matter if you ahve 2 gigs of ram...if you want the os to use the ram as efficiently as possible, you are going to have to have at least trhee gigs of pf available in the case two gigs of ram.

    of course, there are those of you that will never approach the amount of use where having the correct pagefile will matter one way or another...never the less, the ram that is installed cannot be used to it's full potential, without the proper pagefile size

    I really am amazed at how this notion of "if you have alot of ram you can get by with a smaller pagefile".

    if your your pagefile is too small, then you are not using the ram you ahve installed as well as it could be used

    if you subscribe to this idea, then you are not following the true function of a pagefile
     
  13. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    rather then post a link, I think this is a pretty good spot to repost the analogy, so everybody gets a better idea of how the pagefile works;

    This does a good job explaining the pagefile, for those like me, that enjoy the discussion of it...(who, me?..ya)

    this is pretty close;

    Imagine that the pagefile is a big storage facility, with no walls inside the facility...Ram are the workers, and packages are program information

    The boss, (the os) likes to give all his workers, (ram) to be doing something...anything, even when there is not much to do...so as to make bussiness that much smoother over all...but, he surely wants these workers to be ready to do real work should the occasion arise...so, he has a place to put all the packages they're carrying, so they can carry other packages if it becomes necceassary...that's why he hired so many workers, he wouldn't hire say 512 workers if he didn't intend on using them, would he, so he wants them all to be working, and all to be able to carry lots of packages at once.

    so, while a worker is carrying a package, the boss says, well, if I need him to carry something else, I'll have him put the package he's carrying right over here, ... he thus assigns a spot for all the packages his workers are carrying, but the spot remains empty.

    when the boss sees he is out of spots for the packages, he rents more space, say up the block. this is not as efficient, he doesn't want to turn a client down, does he, and he surely doesn't want to keep a client waiting...at least he can keep bussiness moving in this fassion, and absolutely does not have to turn a client down..(this is expansion, and thank goodness for it

    now, when he runs out of workers for a task, he says, "well, bill is carrying that package for the longest time, and the package has just not been opened, jeeze, I don't think that package will ever get opened, I'm going to have bill wait in the storage spot I gave him, but I won't have him put the package down,untill he absolutely needs to carry another package...this way, if the customer wants to open bills package, (HARDLY LIKELY),he'll be ready, and I won't have bill waiting in the storage area anymore, (boy, I'm glad I had the forsight to do that!)I'll have to put pete in waiting instead of bill.

    you see? it's important for the storage facility to be the right size, so the boss doesn't have to rent space up the block!!!...plus, here's the best part, the boss realizes this inneficient space is not good, so he gets rid of it the very next time he opens the doors for bussiness!!! You see, that;s what some people didn't understand in the past, the ineficient space, was actually extremely efficient fot the moment, and gone on the next day...boom...beutifull!!!

    Obviously, it's important for there to be places up the block to rent, just incase the storage facility is too small.(otherwise, the boss will be forced to put those packages in other peoples yards...unbelievably inneficient)

    but rest assured, if the day comes that the boss needs to rent space up the block, the next day, the owner, (you), should build a bigger storage facility, so you never have to rent ineficient space...you of course will never get mad at the boss for renting more space when it was necceassary, instead, you should give him a raise, and say, "well done, good job"

    there
     
  14. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    and again, the same author;

    ...running without a pagefile 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
     
  15. jonocainuk

    jonocainuk Guest

    aye, i agree wiv dealer... i disabled the pagefile and it caused me pc to go slower... much different to win2k... where i found disabling it made it kinda faster... but q2 didnt work lol so i set it to 20mb - worked like a dream :p

    i got 384mb ram... im guessing 512mb pagefile is a bit big lol

    how much u think i should use? 128mb?
     
  16. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    jano...let the system mangage your pagefile, and you'll be fine

    though I think you'd be better served in emergencies, if you doubled the ram asthe initial minimum, and went to as much as you like up to 4096 for the maximum...make sure the maximum is about 4x ram at least
     
  17. Fungiver

    Fungiver Guest

    I think you misse some of what I had to say. I mentioned the tweak in your registry that forces XP to keep data in memory instead of paging sections of RAM to Hard drive. These tweaks come straight from Microsoft MVPs and quite frankly if they don't know then who does. Your analogy falls short in one area. You assume that XP will use the entire RAM at any given time. This simply isn't so. What can possibly use 512MB of RAM? Unless you are a file server or such there are hundreds of "workers" as you put it without packages. your analogy only works if the OS(boss) has enough packages for all the workers. Don't forget I changed the rules here. HKEY_LOCAL_Machine\system\CurrentControlSet\Control|SessionManager\MemoryManagement DisablePagingExecutive. Double click and change to 1. Now I have changed the rules so that no workers can be idle. In affect they can no longer carry empty packages. They simply stand around until needed. There are other tweaks to go with this. Check out MS MVP KElly at www.kellys-korner-xp.com as well as MS MVP Doug Knox at www.dougknox.com as well as MS MVP Jason Tang. Damn I lost his address.
     
  18. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    reread the quotes I provided, fungiver...that will explain to you your last question as far as where the ram goes, when oyu have an abundance...nothing more I can add to that

    as far as these other tweaks, and what they may or may not accomplish, that discussion is for another thread
     
  19. Fungiver

    Fungiver Guest

    Thankyou for the information. You have now reignited my interest in this Pagefile and RAM controversy. So I have gone to www.aumha.org/a/xpvm.htm to have a look at what they say. This article is directly from Alex Nichol MS MVP -Windows Storage Management. Thanks for the kick in the pants. I am now going to have to do more research. The more you know the more you know how little you know. I may in fact owe you an apology. I did try the purfmon and I'm sorry but there was no noticeable decrease or increase with pagefile on or off. They were vitually the same. Sorry for the pun.
     
  20. Fungiver

    Fungiver Guest

    One more quicky dealer. The perfmon is not a good way to judge how much pagefile is used as the perfmon includes POTENTIAL uses by memory pages that have not been taken up.