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4 GB Ram - 64 bit Windows 7 ultimate RRS feed

  • Question

  • Hi I got 4GB Ram installed. System reports 3.5 GB usable and it detects all 4 GB, but only 3.5 is usable. I have tried RC1 and no issue, only in the RTM i notice this change. Any clue on where to look for and what to look for?
    nraja
    Thursday, October 1, 2009 5:24 AM

Answers

  • Question had to be asked, N.Raja.  Sometimes the obvious does get overlooked!


    In that case check BIOS Setup on your machine to ensure that a feature called 'Enable Memory Remapping' or similar is set to 'Enabled'.  On some motherboards a BIOS update might be needed to ensure full compatibility.  Basically, your motherboard chipset needs to be able to support addressing of 8Gb RAM, and support the Memory remapping feature.  Otherwise it won't fully utilise 4Gb RAM under 64-bit Windows.


    http://support.microsoft.com/default.aspx/kb/929605/en-us
    • Proposed as answer by Techwrighter Friday, October 2, 2009 12:41 PM
    • Marked as answer by Ronnie VernonMVP Saturday, October 3, 2009 9:14 AM
    Thursday, October 1, 2009 7:07 AM

All replies

  • Right-click 'Computer' and choose 'Properties'.


    On the System info box which appears, does the entry for "Installed memory (RAM)" read - 4Gb (3.5Gb usable)?

    If so, then does the next line underneath read - "System type - 32-bit Operating system"?



    What you are reporting is the entry which you should be seeing for a 32-bit Windows 7 install, not a 64-bit Windows 7 install.  Perhaps you inadvertently used a 32-bit Windows install disk?
    Thursday, October 1, 2009 6:23 AM
  • Hi, it clearly reports as System Type: 64-Bit Operating System. I was clear that i have used 64 bit disk, since i have tried loading the same disk on a Net Book and could not succeed. Hence I am quite sure that i used 64 bit media.
    nraja
    Thursday, October 1, 2009 6:32 AM
  • Question had to be asked, N.Raja.  Sometimes the obvious does get overlooked!


    In that case check BIOS Setup on your machine to ensure that a feature called 'Enable Memory Remapping' or similar is set to 'Enabled'.  On some motherboards a BIOS update might be needed to ensure full compatibility.  Basically, your motherboard chipset needs to be able to support addressing of 8Gb RAM, and support the Memory remapping feature.  Otherwise it won't fully utilise 4Gb RAM under 64-bit Windows.


    http://support.microsoft.com/default.aspx/kb/929605/en-us
    • Proposed as answer by Techwrighter Friday, October 2, 2009 12:41 PM
    • Marked as answer by Ronnie VernonMVP Saturday, October 3, 2009 9:14 AM
    Thursday, October 1, 2009 7:07 AM
  • do you have onboard graphics?  most onboard graphics do not have dedicated video memory.  They use the main memory and that memory is unavailable to the OS
    • Proposed as answer by DrX69 Thursday, October 1, 2009 8:35 PM
    Thursday, October 1, 2009 5:59 PM
  • Shaon Shan, this topic refers to 64-bit Windows, not 32-bit Windows.  I'm sure you'll find that the relevent answer is in my post above, as explained in the KB article linked in that post.
    Friday, October 2, 2009 12:43 PM
  • Yes and sorry for the incorrect information.
    Tuesday, October 6, 2009 1:46 AM
  • Thanks Guys. How do i find whether the graphics card consumes the RAM, and how much is taken by it as well as where to we tune to our needs. I dont find any settings or visibility to it.

    Thank U.
    nraja
    Saturday, October 10, 2009 12:52 AM
  • Also to note that there is no Memory Remapping option in the BIOS setting. This has even been discussed in many of the Dell Community forums. In this case, do we have any other work arounds to enable, by a 3rd party app or anyt other menas?. I am running on Dell Dimension 9150..
    nraja
    Saturday, October 10, 2009 1:05 AM
  • The issue can also be caused if the motherboard only has a 32 bit address bus. I'm trying to search for detailed information for the motherboard on Dimension 9150. Will edit this post later if anything can be found.

    Edit: Here is a third party website which provided detailed information for Intel 945 Series motherboard. Dimension is using an Intel 945P Express motherboard. From the table, the max Memory Capacity is 4GB so I think it only has 32 bit address bus.


    http://www.pcstats.com/articleview.cfm?articleid=2068&page=2

     

    Wednesday, October 14, 2009 9:20 AM
  • Thanks once Again. The big surprise for me was Windows 7 RC1. When I was running that, I could find and all 4GB was usable. When I upgraded to RTM version of Windows, this issue has started.
    nraja
    Wednesday, October 14, 2009 4:22 PM
  • si with teh 945 chipset, is there any reason to install Win 7 64-bit or should I jsut stay with 32 bit?  I have a Dell Mobile Precision M65 withn two 2GB sticks of RAM.

    I did install the 64 bit and get the same issues noted above.  4.00 GB (3.25 GB Usable).



    thanks,

    Mike
    Monday, November 9, 2009 1:15 PM
  • I would stick with 32-bit, unless you have software that is only available in a 64-bit version. Otherwise, it's actually going to hurt - since 64-bit software needs more base RAM to begin with. (Pointers, by default, are 64-bit, not 32-bit as an example)

    Look at the minimum requirements, and you will see the 64-bit version requires 2x the RAM of the 32-bit version for this reason.

    Keep in mind, there may be some other good reasons for going to 64-bit processing that might offset the effective loss of RAM. You can allocate more memory to a given process in a 64-bit OS than you can in a 32-bit OS. If you have an app that requires more than 2GB of Address space, a 64-bit version is a quick fix for that. (Yes, PAE will work on 32-bit systems, but most software can't take advantage of it.)

    Fortunately, the keys are cross-architecture, so you can use your product key on either type of install. If you have a retail key, you can install the 64-bit version on your next PC and move the license.
    Monday, November 9, 2009 10:58 PM

  • Shaon Shan is correct about the Intel 945 chipset.  It is strictly 32bit and does NOT support REMAP.  Some of the dram beneath the 4G boundary is simply lost.


    Here's the 945 technical datasheet (PDF):   Intel® 945G/945GZ/945GC/945P/945PL Express Chipset Family Datasheet




    As a comparison, here's the datasheet of the slightly newer 965 chipset (PDF):   Mobile Intel® 965 Express Chipset Family Datasheet .  The mobile-965 likewise supports only 4G, but does include REMAP support.  It nicely explains on page 55 what the difference is:

    "Earlier chipsets supported a maximum main memory size of 4-GB total memory. This would result in a hole between TOLUD (Top of Low Usable DRAM) and 4 GB when main memory size approached 4 GB, resulting in a certain amount of physical memory being inaccessible to the system.

    The new reclaim configuration registers (TOUUD, REMAPBASE, REMAPLIMIT) exist to reclaim lost main memory space. The greater than 32-bit reclaim handling are handled similar to other MCHs [Memory Controller Hubs]."





    Carey, I'm getting very disappointed with you.  You failed to delete this post of mine while you were deleting all the rest.


    Well, here it is.   Come and get it!

    Monday, November 23, 2009 7:45 AM