4 gig memory installed only 3 showing up on vista ultimate x64

As stated, running vista ultimate x64 with 4 GB installed.  They show up in BIOS, but no on system control panel or task manager.  I've seen several answers about this, but always they point out that it applies to 32 bit vista and usually mention that 64 bit vista is capable.

Is there some bcdedit.exe command I need to change for it to show up?

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YGregersenConnect With a Mentor Commented:
In my BIOS I had to enable 'Memory Remapping' before the OS would see it all. This was under the Northbridge settings. Your Dell does not have this setting it is a limitation of the chipset and your BIOS. Here are the related articles below.

Sorry Fermat1.


The problem is that the Dimension E510 uses the Intel 945G chipset, a chipset that does not support over 4GB of address space.  
The following Microsoft Knowledge Base article explains the hardware and software limitations:
In essence, the chipset must support at least 8GB of address space [33 bits] for there to be any possibility that 64-bit Vista or XP will map the various I/O areas (including your graphics card's on-board memory) above the 4GB address space boundary.  If the hardware is incapable of this mapping, these areas will be mapped within the available 4GB address space.  In this event, the corresponding part of the RAM will be unused.
Brian PiercePhotographerCommented:
If you are sure its the 64 bit version of Vista?

Click the Windows blob, (start button) type "SYSTEM" in the Start Search box, and click SYSTEM in the Programs list.
Look under System Type - it will confirm 32 or 64bit OS.
For a 64-bit version operating system: 64-bit Operating  

If it is 64 bit then, it could be that its a limitation of the motherboard - check the manual
Is your video card using some of the RAM as shared memory ?
Fermat1Author Commented:
I can definitely confirm that it is 64 bit Vista.

The motherboard has a maximum of 4 GB, and 4 GB does show up in BIOS.

How would I check if my video card is using the shared memory?  When I had 2 GB installed, all 2 GB showed up.  Why would a full GB of memory be used for devices anyway just because I jumped to 4 GB?
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sounds like a limitation of your motherboard's chipset to me.

could you find out what chipset you have and post back?
Brian PiercePhotographerCommented:
If memory was being used by your graphics card then it would use memory regardless of wether 2Gb or 4Gb was installed so its not that.

Given that you are sure that it is indeed the 64bit version that only leaves the Motherboard. Check with the Motherboard manufacturers web site - and see if a BIOS update is available.
As stated above , there are more issues to contend with than the 64bit vs 32bit question, when trying to get all 4GB of memory seen by the operating system.
Here is an interesting link from HP that mentions the chipset limitation issue even when running a 64bit OS.
It states-->"In contrast, some 64-bit capable systems use 32-bit chipsets, limiting physical memory addressing to the 4 GB limit even though Windows XP Professional x64 Edition is installed. The HP xw4200 is such a system (like all systems based on the Intel 925 Express chipset) and it continues to typically allocate between 3 and 3.4 GB of RAM."<--
Fermat1Author Commented:
Ok, sounds like my motherboard is the issue.  I'm not exactly sure how to find out what it is.  It is a Dell, so I guess I'll give them a call.

I'll post back with the details. Thanks.
Fermat1Author Commented:

SIW reports the following on my motherboard:

Property      Value
Manufacturer      Dell Inc.
Model      0RY007
Version      ÿÿÿ
Serial Number      ..CN7360479402OT.
CPU      Intel Core 2 Duo
Cpu Socket      LGA775 [Socket 775]
Processor Upgrade      ZIF Socket
System Slots      2 PCI
Memory Summary      
Location      System board or motherboard
Maximum Capacity      4096 MBytes
Memory Slots      4
Error Correction      None
Name      Physical Memory Array
Use      System memory
Warning!      Accuracy of DMI data cannot be guaranteed
MarkConnect With a Mentor Commented:
That motherboard can come with a variety of chipsets, from the P35, and G33 which supports 8GB of memory addressability  to the P31,G31 which only supports 4GB of memory addressability.

Try CPUz to see if you can identify the chipset
Fermat1Author Commented:
Sparkmaker, CPUz reports my mainboard chipset as "P35/G33/G31".  Why does it list three?  Reading the details, both G33 and P35 list 1333 MHz FSB, where G31 lists only 1066 MHz.  CPUz reports 1333 MHz FSB, so does this mean I have either G33 or P35?

If I have G33 or P35, then 8 GB is addressable and YGregersen's article shouldn't apply, right?

YGregersenConnect With a Mentor Commented:
The article actually states that even though you can address more (lets say you have the P935) memory if the BIOS does not support memory remapping - then you will not be able to see all of it.


According to the following Microsoft Knowledge Base article, "This behavior is the expected result of certain hardware and software factors."   Note that the article states that it applies to both 32-bit and 64-bit versions of Vista (although the article text explains it with respect to 32-bit versions of Vista).
Essentially, as the article indicates, the same factors that apply to 32-bit Vista also apply to 64-bit Vista:  to avoid driver compatibility issues, both Microsoft and various system vendors have chosen not, by default, to remap above the 4 GB addressing boundary certain areas that are normally below that boundary.
The article specifies how, as a workaround, a 64-bit version of Vista can use all 4 GB of memory.
However, one of the requirements of that workaround is that "the chipset must support at least 8GB of address space."  (The article lists the following Intel chipsets as among those having that capability:  975X, P965, 955X on Socket 775.)
Another of the requirements is that the BIOS must support the memory remapping feature, and it must be enabled.  It also states: "Many consumer-oriented computers may not support the memory remapping feature."
For Windows Vista to use all 4 GB of memory on a computer that has 4 GB of memory installed, the computer must meet the following requirements:
"      The chipset must support at least 8 GB of address space. Chipsets that have this capability include the following:
"      Intel 975X
"      Intel P965
"      Intel 955X on Socket 775
"      Chipsets that support AMD processors that use socket F, socket 940, socket 939, or socket AM2. These chipsets include any AMD socket and CPU combination in which the memory controller resides in the CPU.
"      The CPU must support the x64 instruction set. The AMD64 CPU and the Intel EM64T CPU support this instruction set.
"      The BIOS must support the memory remapping feature. The memory remapping feature allows for the segment of system memory that was previously overwritten by the Peripheral Component Interconnect (PCI) configuration space to be remapped above the 4 GB address line. This feature must be enabled in the BIOS configuration utility on the computer. View your computer product documentation for instructions that explain how to enable this feature. Many consumer-oriented computers may not support the memory remapping feature. No standard terminology is used in documentation or in BIOS configuration utilities for this feature. Therefore, you may have to read the descriptions of the various BIOS configuration settings that are available to determine whether any of the settings enable the memory remapping feature.
"      An x64 (64-bit) version of Windows Vista must be used.
Which Dell model is this. Do you have a service tag number we can use to check for BIOS updates and such?
Fermat1Author Commented:
It is a dell inspiron 530.  I just downloaded and installed the latest BIOS from dell, 1.0.5.  I see no remapping feature.  Hopefully it will appear someday for me. :)

I think I understand the issue now.  Thanks.
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