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4gig on D820 and D620 x64

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4gig on D820 and D620 x64

  • My company has just bought four new 64bit D620 with 4GB RAM. But we can only use the 3,25gig. Tried using them in some D820 64bit, but with the same result. I thought the that problem was with 32bit only. Can anyone help? 
  • The limitation is one of the chipsets used on these systems - remember that in addition to part of your RAM being used for video purposes, other blocks of RAM are used by the chipset to manage the functions of the system board.


  • ejn63 wrote:
    The limitation is one of the chipsets used on these systems - remember that in addition to part of your RAM being used for video purposes, other blocks of RAM are used by the chipset to manage the functions of the system board.




    The problem is actually that the 945 chipset seems to not support memory remapping, the "blocks of RAM" are not used, a part of the 32bit address space is reserved for this devices. Other chipsets are able to map in the memory after the 4GB again.

    I already asked... is the D830 doing memory remapping?
  • I looked the issue up:
    http://download.intel.com/design/mobile/datashts/30921904.pdf page 317:
    "Addressing of memory ranges larger than 4 GB is not supported. The HREQ [4:3] FSB pins are decoded to determine whether the access is above or below 4 GB."

    So on the D620/D820 it's just not doable to make use of more than 3.2 GB or soemthing like that.

    The 965 (in the D630/D830 etc.) supports memory remapping/reclaiming memory definitively
    http://download.intel.com/design/mobile/datashts/31627303.pdf page 55

    Now the question is just is the BIOS is making use of this feature.

    Message Edited by ijuz on 06-28-2007 09:46 PM
  • We have purchased many D520's, D620's and D630's with 4 GB of memory with the assumption that we would be able to utilize. As you know the extra cost for this amount of memory is high.  We can only utilize between 3 and 3.3 GBytes, depending on the model.
     
    We have escalated to Dell several times. They have never came back with an official response. We are very dissapointed and are looking at other vendors. We have been a Dell shop for 12 years, I really dont want to move away, but with absolutly no response from them on this, they are forcing our hand.
  • This is an issue with the current BIOS available on the D820 laptops as well as I am sure other model latitude laptops. If you look in the BIOS of the machine, you will see that it is only passing approx 3.25 gig to the system on startup. My company has escalated this to Dell with a support request to fix the memory issue as they are advertising MAX memory capacity on the D820's at 4gig, but the system BIOS only gives the OS 3.25. I will post what response I get from dell on this issue.
  • I hate to resurrect a 4.5 year old thread, but this is STILL an issue, at least in the Latitude D520, BIOS version A08.

    It's enfuriating to be limited to 3.25GB of RAM.  Since the BIOS just says that the memory "isn't available for use" (paraphrasing a bit there), I can only assume that the memory is reserved for the video card.  Either way, end users like me desperately need a BIOS option that allows us to choose the amount of memory reserved for "system use".  Since the system current reserves 768 MB of RAM for system use (which is absurd), I'm thinking the BIOS could provide the following selections as options:

    0MB - (this is only an option if the video card does NOT share the system memory)

    64MB - (probably also too low for the same reasons as the 0MB case)

    128MB - (this should be fine)

    256MB

    512MB

    768MB - (for backward compatibility, in case OS drivers depend on the 768MB reservation - which they certainly SHOULD NOT).

    I would really appreciate a response from someone that can provide more insight into this issue.  If Dell doesn't want to release another BIOS update (last one, A08, was released in 2009), Dell could/should provide the following instead:

    1) A detailed technical explanation for why the limit exists

    2) Hardware manuals and user guides for all BIOS related components

    3) Source code for the latest BIOS so that those interested could fix BIOS related issues.  This is especially important because the latest BIOS was released in 2009, and I can only assume that Dell has no plans for further BIOS updates.

    All of the above would be very helpful in finding a fix to this nagging issue.

  • How can we get Dell's attention to address this matter?

    I just migrated to win7 x64 and learned this sad fact No