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XP Pro RAM

Discussion in 'Windows XP' started by Kernel, May 31, 2010.

  1. Kernel

    Kernel Flightless Bird

    If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just let
    it choose? The reason being is I'm going to build a new PC and it appears
    that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.

    TIA.
     
  2. John John - MVP

    John John - MVP Flightless Bird

    Kernel wrote:
    > If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just let
    > it choose? The reason being is I'm going to build a new PC and it appears
    > that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.


    Sure, no problem at all. Install 4GB and the OS will use what it can,
    the rest will just go unused but it won't cause any problems.

    John
     
  3. Kernel

    Kernel Flightless Bird

    Thanks for the speedy answer. Now I'm off shopping for some parts...


    "John John - MVP" <audetweld@nbnot.nb.ca> wrote in message
    news:-O5DUpCQALHA.5808@TK2MSFTNGP02.phx.gbl...
    > Kernel wrote:
    >> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just
    >> let it choose? The reason being is I'm going to build a new PC and it
    >> appears that 4 GB may be cheaper/easier to find that one 2 GB and one 1
    >> GB.

    >
    > Sure, no problem at all. Install 4GB and the OS will use what it can, the
    > rest will just go unused but it won't cause any problems.
    >
    > John
     
  4. John John - MVP

    John John - MVP Flightless Bird

    You're welcome, have fun shopping.

    John

    Kernel wrote:
    > Thanks for the speedy answer. Now I'm off shopping for some parts...
    >
    >
    > "John John - MVP" <audetweld@nbnot.nb.ca> wrote in message
    > news:-O5DUpCQALHA.5808@TK2MSFTNGP02.phx.gbl...
    >> Kernel wrote:
    >>> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just
    >>> let it choose? The reason being is I'm going to build a new PC and it
    >>> appears that 4 GB may be cheaper/easier to find that one 2 GB and one 1
    >>> GB.

    >> Sure, no problem at all. Install 4GB and the OS will use what it can, the
    >> rest will just go unused but it won't cause any problems.
    >>
    >> John

    >
    >
     
  5. Ken Blake, MVP

    Ken Blake, MVP Flightless Bird

    On Mon, 31 May 2010 13:28:18 -0700, "Kernel" <kernel64@bosworth33net>
    wrote:

    > If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just let
    > it choose? The reason being is I'm going to build a new PC and it appears
    > that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.




    Yes, that's no problem.

    But bear in mind that "XP can only use 3 GB of RAM" is not completely
    accurate. Here's the correct info:

    All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
    address space (64-bit versions can use much more). That's the
    theoretical upper limit beyond which you can not go.

    But you can't use the entire 4GB of address space. Even though you
    have a 4GB address space, you can only use *around* 3.1GB of RAM.
    That's because some of that space is used by hardware and is not
    available to the operating system and applications. The amount you can
    use varies, depending on what hardware you have installed, but can
    range from as little as 2GB to as much as 3.5GB. It's usually around
    3.1GB.

    Note that the hardware is using the address *space*, not the actual
    RAM itself. If you have a greater amount of RAM, the rest of the RAM
    goes unused because there is no address space to map it to.


    --
    Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    Please Reply to the Newsgroup
     
  6. Twayne

    Twayne Flightless Bird

    In news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com,
    Ken Blake, MVP <kblake@this.is.an.invalid.domain> typed:
    > On Mon, 31 May 2010 13:28:18 -0700, "Kernel"
    > <kernel64@bosworth33net> wrote:
    >
    >> If XP can only use 3 GB of RAM, could I install two 2 GB
    >> sticks and just let it choose? The reason being is I'm
    >> going to build a new PC and it appears that 4 GB may be
    >> cheaper/easier to find that one 2 GB and one 1 GB.


    Ken is right; you should have no problems. In fact, depending on the mobo
    and setup, you might not even be able to use a 2 + 1 GB mix of RAM modules.
    Many systems require them to be inserted in pairs, and then go even farther
    and insist that they be the same size for each module in the pair, so a 2 +
    1 might be disallowed anyway
    ..
    Further, if say, you have 4 memory slots and two 2Gig modules, the
    modules may be requied to occuply slots 0 and 2 only. Or slot 0 only if a 4
    GB module is allowed; often they are not. Slot 0 must always be occupied.

    It sounds a lot worse in words than it really is. All it really means is,
    be sure to read the documentation that explains how RAM expansion is
    accomplished for your specific mobo if you aren't already certain. For
    instance on my Dell T3400 I cannot use any RAM module greater than 2 GB
    each. If there is to be more than one RAM module, they must be installed in
    pairs 0, 2 and then 1,3, plus each module of each pair must be the same
    size.
    They can vary in speed capabilities, but the entire RAM complement will
    run at the slowest speed of the slowest module in the set/s.

    The
    >
    >
    >
    > Yes, that's no problem.
    >
    > But bear in mind that "XP can only use 3 GB of RAM" is not
    > completely accurate. Here's the correct info:


    It's completely accurate enough for the purpose of the querant and all
    you've really done here is provided information that could "confuse the
    issue with facts".

    >
    > All 32-bit client versions of Windows (not just Vista/XP/7)
    > have a 4GB address space (64-bit versions can use much
    > more). That's the theoretical upper limit beyond which you
    > can not go.


    "Theoretical"?? Hardly. 4 GB or however you want to count it, is EXACTLY
    the number of address spaces available. It's not theoretic; it's very real
    and the laws of physics makes sure it remains that way.
    >
    > But you can't use the entire 4GB of address space.


    Wrong: You CAN and DO use the entire 4 GB of address space. There is no
    "wasted" RAM, this time in theory, because some addresses, though they
    exist, may never be used in every machine although they are still assigned,
    and there are a few used for software setups too, plus some of the BIOS
    needs.

    Even
    > though you have a 4GB address space, you can only use
    > *around* 3.1GB of RAM. That's because some of that space is
    > used by hardware and is not available to the operating
    > system and applications.


    Hardware is NOT the only address sets that are assigned by the system when
    it starts up.

    The amount you can use varies, but is more likely to be in the 3.2 to 3.7
    area for most retail machines sold today.

    It isn't the "amount you can use", it's the amount that is LEFT available.
    Unless you do something silly, you WILL use it, not "can" use it.

    > depending on what hardware you have installed, but can
    > range from as little as 2GB to as much as 3.5GB. It's
    > usually around
    > 3.1GB.


    Very, very few people, if any, will ever see 2 Gig used by system hardware
    on a standard XP desktop machine. 2 GB however is often considered the
    "sweet spot" or "point where diminishing returns" will soon occur.

    More accurately stated, the system first assigns the system addresses from
    the top of the 4 GB of address space downward. Since an address cannot be
    used twice, those addresses are NOT available any longer to be used for
    anything else. Whatever is left after this assignment set is completed is
    what you can have for actual Random Access Memory addressing.
    If you find you only have 2 GB of RAM available when you install 4,
    you're either not here asking these questions because you already know more
    than most people here, OR more likely you have a physical problem with your
    hardware. RAM or its support cktry has a problem, is mismatched, mis-setup,
    or some other hardware issue is going on. In fact, if you see less than 3 GB
    available when you have 4 installed, you should still make certain you know
    why or you probably wouldn't be the type of person who would need this
    newsgroup.
    >
    > Note that the hardware is using the address *space*, not


    No, it's using the "ADDRESS", of which there are 4GB of separately
    addressable locations in the RAM modules.

    > the actual RAM itself. If you have a greater amount of RAM,
    > the rest of the RAM goes unused because there is no address
    > space to map it to.


    More accurately, the addresses are already used and thus cannot be used to
    address anything else.

    And we won't even think of discussing RAM Extenders to go beyond 4 GB on an
    XP machine although they are available as specialty setups.

    If you're going to try to explain things, at least try to be accurate about
    them. I'm no expert or technical writer, but your post gave me a couple of
    completely errant pieces of advice.

    HTH,

    Twayne`
     
  7. VanguardLH

    VanguardLH Flightless Bird

    Kernel wrote:

    > John John wrote ...
    >
    >> Kernel wrote:
    >>
    >>> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and
    >>> just let it choose? The reason being is I'm going to build a new
    >>> PC and it appears that 4 GB may be cheaper/easier to find that one
    >>> 2 GB and one 1 GB.

    >>
    >> Sure, no problem at all. Install 4GB and the OS will use what it
    >> can, the rest will just go unused but it won't cause any problems.

    >
    > Thanks for the speedy answer. Now I'm off shopping for some
    > parts...


    Plus you're likely to retain the dual-channel feature of your memory if
    you use matching RAM modules. You lose dual-channel (if your mobo has
    it and it is enabled) if you mix a 2GB module with a 1GB module.

    From Newegg but without any details of your hardware so I looked up
    240-pin DDR2 1066 memory (same Geil brand for all):

    4GB (2 x 2G8): $110
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820144213

    2GB (1 x 2G8): $57
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820144359
    1GB (1 x 1G8): $30
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820231143

    So 4GB (2 x 2G8) was $110 while 3GB (1 X 2GB + 1 x 1G8) was $87. Yes,
    you would save $23 but you would lose any dual-channel feature. Whether
    dual-channel is important depends on if you are currently hitting your
    max physical memory. In benchmarks (and not in real use), dual-channel
    gives you all of about 7% performance increase, if that. If you're
    running out of physical memory, you'll get far more speed increase by
    having more memory than for the loss of dual-channel. So 2GB+1GB could
    end up boosting the speed of your host even with the loss of dual-
    channel mode; however, 2GB+2GB would also give you the speed boost while
    retaining dual-channel mode.

    http://en.wikipedia.org/wiki/Dual-channel_architecture

    Of course, when you later move to a 64-bit OS then you can make use of
    that other 1GB of memory. Meanwhile, you could try to use some OS
    tweaks, like the one that keeps more of the OS kernel in memory; see:

    http://msdn.microsoft.com/en-us/library/ee377084(BTS.10).aspx
    http://support.microsoft.com/kb/184419

    about DisablePaging Executive. Warning: some drivers actually expect to
    get paged out and will fail (crash) if not allowed to do so.

    You could also play with the /3GB boot.ini option. The /3GB switch
    gives more memory to user process space (i.e., your apps) but is useless
    unless those user apps use the IMAGE_FILE_LARGE_ADDRESS_AWARE in the
    process header. You probably don't have have any apps that can access
    more than 2GB of memory.

    http://www.microsoft.com/whdc/system/platform/server/pae/paemem.mspx
    http://support.microsoft.com/kb/291988

    Have you actually read the manual for your mobo to determine what memory
    configurations it will allow?
     
  8. Kernel

    Kernel Flightless Bird

    Thanks. I'm planning on building a new system, Gigabyte AM3 to get SATA 3
    and USB 3. But for now I'll be using an extra copy of XP Pro that I have
    laying around, hence the 3G RAM question. I'll use two 2 GBs for now then
    add more when I upgrade OS.


    "Ken Blake, MVP" <kblake@this.is.an.invalid.domain> wrote in message
    news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com...
    > On Mon, 31 May 2010 13:28:18 -0700, "Kernel" <kernel64@bosworth33net>
    > wrote:
    >
    >> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just
    >> let
    >> it choose? The reason being is I'm going to build a new PC and it
    >> appears
    >> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.

    >
    >
    >
    > Yes, that's no problem.
    >
    > But bear in mind that "XP can only use 3 GB of RAM" is not completely
    > accurate. Here's the correct info:
    >
    > All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
    > address space (64-bit versions can use much more). That's the
    > theoretical upper limit beyond which you can not go.
    >
    > But you can't use the entire 4GB of address space. Even though you
    > have a 4GB address space, you can only use *around* 3.1GB of RAM.
    > That's because some of that space is used by hardware and is not
    > available to the operating system and applications. The amount you can
    > use varies, depending on what hardware you have installed, but can
    > range from as little as 2GB to as much as 3.5GB. It's usually around
    > 3.1GB.
    >
    > Note that the hardware is using the address *space*, not the actual
    > RAM itself. If you have a greater amount of RAM, the rest of the RAM
    > goes unused because there is no address space to map it to.
    >
    >
    > --
    > Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    > Please Reply to the Newsgroup
     
  9. Ken Blake, MVP

    Ken Blake, MVP Flightless Bird

    On Mon, 31 May 2010 17:29:01 -0700, "Kernel" <kernel64@bosworth33net>
    wrote:

    > Thanks.



    You're welcome. Glad to help.



    > I'm planning on building a new system, Gigabyte AM3 to get SATA 3
    > and USB 3. But for now I'll be using an extra copy of XP Pro that I have
    > laying around, hence the 3G RAM question. I'll use two 2 GBs for now then
    > add more when I upgrade OS.



    Just one more point: How much RAM you need for good performance is
    *not* a one-size-fits-all situation. You get good performance if the
    amount of RAM you have keeps you from using the page file
    significantly, and that depends on what apps you run. Most people
    running a typical range of business applications under XP find that
    somewhere around 512MB works well, others need more. Almost anyone
    will see poor performance with less than 256MB, but few people need as
    much as 3GB. Some people, particularly those doing things like editing
    large photographic images, can see a performance boost by adding even
    more than 512MB--sometimes much more.



    > "Ken Blake, MVP" <kblake@this.is.an.invalid.domain> wrote in message
    > news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com...
    > > On Mon, 31 May 2010 13:28:18 -0700, "Kernel" <kernel64@bosworth33net>
    > > wrote:
    > >
    > >> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just
    > >> let
    > >> it choose? The reason being is I'm going to build a new PC and it
    > >> appears
    > >> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.

    > >
    > >
    > >
    > > Yes, that's no problem.
    > >
    > > But bear in mind that "XP can only use 3 GB of RAM" is not completely
    > > accurate. Here's the correct info:
    > >
    > > All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
    > > address space (64-bit versions can use much more). That's the
    > > theoretical upper limit beyond which you can not go.
    > >
    > > But you can't use the entire 4GB of address space. Even though you
    > > have a 4GB address space, you can only use *around* 3.1GB of RAM.
    > > That's because some of that space is used by hardware and is not
    > > available to the operating system and applications. The amount you can
    > > use varies, depending on what hardware you have installed, but can
    > > range from as little as 2GB to as much as 3.5GB. It's usually around
    > > 3.1GB.
    > >
    > > Note that the hardware is using the address *space*, not the actual
    > > RAM itself. If you have a greater amount of RAM, the rest of the RAM
    > > goes unused because there is no address space to map it to.
    > >
    > >
    > > --
    > > Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    > > Please Reply to the Newsgroup

    >


    --
    Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    Please Reply to the Newsgroup
     
  10. Kernel

    Kernel Flightless Bird

    I'd also like to thank all of the MVPs, and the other guru's, who have
    helped soooo many people over the years. I've used the Google Advanced
    Search with this NG a zillion times, and always found the answer. In fact I
    found a lot of answers and developed a long list of tips that I've saved.
    Mr. Ken Blake, and God Rest His Soul Alex Nichol are only two of the
    standouts; everyone was always ready to help, even ol' Alias. I don't mean
    to try and rank the talent, you are all 'farmers' (a farmer is a person who
    is outstanding in his field).

    The forums will never be as easy to use, to search, and to get good help as
    this service.

    Thank you all.


    "Ken Blake, MVP" <kblake@this.is.an.invalid.domain> wrote in message
    news:bdn8069al33n9mg5kf5cnuek1ubqqap576@4ax.com...
    > On Mon, 31 May 2010 17:29:01 -0700, "Kernel" <kernel64@bosworth33net>
    > wrote:
    >
    >> Thanks.

    >
    >
    > You're welcome. Glad to help.
    >
    >
    >
    >> I'm planning on building a new system, Gigabyte AM3 to get SATA 3
    >> and USB 3. But for now I'll be using an extra copy of XP Pro that I have
    >> laying around, hence the 3G RAM question. I'll use two 2 GBs for now
    >> then
    >> add more when I upgrade OS.

    >
    >
    > Just one more point: How much RAM you need for good performance is
    > *not* a one-size-fits-all situation. You get good performance if the
    > amount of RAM you have keeps you from using the page file
    > significantly, and that depends on what apps you run. Most people
    > running a typical range of business applications under XP find that
    > somewhere around 512MB works well, others need more. Almost anyone
    > will see poor performance with less than 256MB, but few people need as
    > much as 3GB. Some people, particularly those doing things like editing
    > large photographic images, can see a performance boost by adding even
    > more than 512MB--sometimes much more.
    >
    >
    >
    >> "Ken Blake, MVP" <kblake@this.is.an.invalid.domain> wrote in message
    >> news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com...
    >> > On Mon, 31 May 2010 13:28:18 -0700, "Kernel" <kernel64@bosworth33net>
    >> > wrote:
    >> >
    >> >> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and
    >> >> just
    >> >> let
    >> >> it choose? The reason being is I'm going to build a new PC and it
    >> >> appears
    >> >> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.
    >> >
    >> >
    >> >
    >> > Yes, that's no problem.
    >> >
    >> > But bear in mind that "XP can only use 3 GB of RAM" is not completely
    >> > accurate. Here's the correct info:
    >> >
    >> > All 32-bit client versions of Windows (not just Vista/XP/7) have a 4GB
    >> > address space (64-bit versions can use much more). That's the
    >> > theoretical upper limit beyond which you can not go.
    >> >
    >> > But you can't use the entire 4GB of address space. Even though you
    >> > have a 4GB address space, you can only use *around* 3.1GB of RAM.
    >> > That's because some of that space is used by hardware and is not
    >> > available to the operating system and applications. The amount you can
    >> > use varies, depending on what hardware you have installed, but can
    >> > range from as little as 2GB to as much as 3.5GB. It's usually around
    >> > 3.1GB.
    >> >
    >> > Note that the hardware is using the address *space*, not the actual
    >> > RAM itself. If you have a greater amount of RAM, the rest of the RAM
    >> > goes unused because there is no address space to map it to.
    >> >
    >> >
    >> > --
    >> > Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    >> > Please Reply to the Newsgroup

    >>

    >
    > --
    > Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    > Please Reply to the Newsgroup
     
  11. Ken Blake, MVP

    Ken Blake, MVP Flightless Bird

    On Mon, 31 May 2010 19:46:07 -0700, "Kernel" <kernel64@bosworth33net>
    wrote:

    > I'd also like to thank all of the MVPs, and the other guru's, who have
    > helped soooo many people over the years. I've used the Google Advanced
    > Search with this NG a zillion times, and always found the answer. In fact I
    > found a lot of answers and developed a long list of tips that I've saved.
    > Mr. Ken Blake, and God Rest His Soul Alex Nichol are only two of the
    > standouts;



    You're welcome, and thank you very much for such kind words. I'm not
    sure I deserve it, but it's a great honor to be ranked with Alex
    Nichol, who was one of my newsgroup heroes.



    --
    Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003
    Please Reply to the Newsgroup
     

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