I recently upgraded to a 64-bit OS so that I could take advantage of all my RAM. I have 2x1GB and 2x 512MB, I also have an Nvidia 8600GTS with 512MB video ram. Under Windows XP Pro SP3 only 2.25G was ever available. As I understand it, only 4GB of memory is possible with a 32-bit system, and even that is not likely as memory addressing space is used up by video card RAM, and other devices to some extent.
So immagine my surprise when I buy and upgrade to Windows 7 64-bit, only to discover in my system properties "3 GB (2.25 GB usable)"
To address some of the common solutions or explanations I've read about and tried before posting:
My BIOS sees the 3 GB of RAM. My BIOS supports up to 4 GB of RAM.
I tested the memory, and none of it is faulty.
I even removed alternating pieces of RAM and tried using them individually, they were all recognized and worked.
Yes, I am sure I'm running a 64-bit OS.
There is no memory remapping setting in my BIOS.
I've tried running msconfig and going to the boot tab, then advanced, and making sure the max memory isn't being limited.
So, anyone know why my memory isn't able to be used under my 64-bit OS? How can I fix this?
Possibly relevant system specs from System Information (I pruned a lot out)
System Information report written at: 01/26/10 16:17:52
System Name: FROSTWYRM
OS Name Microsoft Windows 7 Professional
Version 6.1.7600 Build 7600
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name FROSTWYRM
System Manufacturer Dell Inc.
System Model Dimension 8400
System Type x64-based PC
Processor Intel(R) Pentium(R) 4 CPU 3.00GHz, 2992 Mhz, 1 Core(s), 2 Logical Processor(s)
BIOS Version/Date Dell Inc. A05, 3/16/2005
SMBIOS Version 2.3
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "6.1.7600.16385"
User Name Not Available
Time Zone Pacific Standard Time
Installed Physical Memory (RAM) 3.00 GB
Total Physical Memory 2.25 GB
Available Physical Memory 1.61 GB
Total Virtual Memory 4.49 GB
Available Virtual Memory 3.65 GB
Page File Space 2.25 GB
Page File C:\pagefile.sys
I/O Port 0x00000000-0x00000CF7 PCI bus
I/O Port 0x00000000-0x00000CF7 Direct memory access controller
I/O Port 0x000003C0-0x000003DF Intel(R) 925X/XE PCI Express Root Port - 2585
I/O Port 0x000003C0-0x000003DF NVIDIA GeForce 8600 GTS
Resource Device Status
0xDC000000-0xDFEFFFFF Intel(R) 925X/XE PCI Express Root Port - 2585 OK
0xDC000000-0xDFEFFFFF NVIDIA GeForce 8600 GTS OK
0x90000000-0xBFFFFFFF Intel(R) 925X/XE PCI Express Root Port - 2585 OK
0xA0000-0xBFFFF Intel(R) 925X/XE PCI Express Root Port - 2585 OK
0xA0000-0xBFFFF PCI bus OK
0xA0000-0xBFFFF NVIDIA GeForce 8600 GTS OK
0xDBF00000-0xDBFFFFFF Intel(R) 82801FB/FBM PCI Express Root Port - 2660 OK
0x8FF00000-0xDFFFFFFF PCI bus OK
0xF0000000-0xFEBFFFFF PCI bus OK
0xDBE00000-0xDBEFFFFF Intel(R) 82801FB/FBM PCI Express Root Port - 2662 OK
0x0000-0x9FFFF System board OK
0x100000-0xFFFFFF System board OK
0x1000000-0x8FE8CBFF System board OK
0xC0000-0xFFFFF System board OK
0xFEC00000-0xFECFFFFF System board OK
0xFEE00000-0xFEEFFFFF System board OK
0xFED20000-0xFED9FFFF System board OK
0xFFB00000-0xFFBFFFFF System board OK
0xFFC00000-0xFFFFFFFF System board OK
0xDE000000-0xDEFFFFFF NVIDIA GeForce 8600 GTS OK
0xA0000000-0xBFFFFFFF NVIDIA GeForce 8600 GTS OK
0xE0000000-0xEFFFFFFF Motherboard resources OK
0xFEDA0000-0xFEDACFFF Motherboard resources OK
0xDFFFFC00-0xDFFFFFFF Standard AHCI 1.0 Serial ATA Controller OK
0xDFFFFA00-0xDFFFFBFF SoundMAX Integrated Digital Audio OK
0xDFFFF900-0xDFFFF9FF SoundMAX Integrated Digital Audio OK
0xDBFF0000-0xDBFFFFFF Broadcom NetXtreme 57xx Gigabit Controller OK
0xDBDDF000-0xDBDDFFFF PCI Modem OK
0xDBD00000-0xDBDFFFFF Intel(R) 82801 PCI Bridge - 244E OK
0xFED00000-0xFED003FF High precision event timer OK
0xFEBFFC00-0xFEBFFFFF Intel(R) 82801FB/FBM USB2 Enhanced Host Controller - 265C OK
Name NVIDIA GeForce 8600 GTS
PNP Device ID PCI\VEN_10DE&DEV_0400&SUBSYS_22891682&REV_A1\4&701F2C4&0&0008
Adapter Type GeForce 8600 GTS, NVIDIA compatible
Adapter Description NVIDIA GeForce 8600 GTS
Adapter RAM 512.00 MB (536,870,912 bytes)
Installed Drivers nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
Driver Version 22.214.171.12407
INF File oem3.inf (Section003 section)
Color Planes Not Available
Color Table Entries 4294967296
Resolution 1280 x 1024 x 60 hertz
Memory Address 0xDE000000-0xDEFFFFFF
Memory Address 0xA0000000-0xBFFFFFFF
Memory Address 0xDC000000-0xDFEFFFFF
I/O Port 0x0000DC80-0x0000DCFF
IRQ Channel IRQ 16
I/O Port 0x000003B0-0x000003BB
I/O Port 0x000003C0-0x000003DF
Memory Address 0xA0000-0xBFFFF
Driver c:\windows\system32\drivers\nvlddmkm.sys (126.96.36.19907, 10.77 MB (11,293,928 bytes), 9/28/2009 12:12 AM)
Im going out on a limb with this - I believe the max addressable space available to you is 4G. That means you will see the same available RAM regardless of a 32 bit or 64 bit OS. That is a fairly old system and 4G would have been almost unheard of back then.... I have seen others report something similar with older systems...
This would explain why you see the exact same amount in XP SP3 32-bit, and Win7 64-bit. 32-bit shouldn't limit you until you get up to 4, but since you are seeing the same in both cases it makes sense that it is a hardware limitation.