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44423
June 6th, 2012 14:00
Not all installed memory being used
My wife's computer is a Dell Dimension 9150, running Windows 7 Home Premium 64-bit.
I just replaced the four 512MB RAM modules with four 1GB RAM modules. However, the system information reads:
Installed Memory (RAM): 4.00GB (3.50 GB usable)
All the documentation I've read suggests that the motherboard has 4GB limit, and as long as I'm using a 64-bit OS, I should be able to address all 4GB. Does anyone know how I can access the remaining 512MB RAM?
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DELL-Shiva R
4 Posts
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June 6th, 2012 16:00
Hi Neal,
Welcome to the Dell Community,
I understand that you have Windows 7 Home Premium 64-bit operating system installed for your Dimension 9150 Computer. Also the memory has been upgraded to 4G (4 X1GB).
To verify the amount of memory installed in the system you could enter the System Setup Menu (or BIOS).
In the BIOS, generally on the first page, the amount of memory installed in the system will be displayed.
Allocated memory is made up of physical memory and any Input/output space needed by devices.
Normally this is not a problem as, when a system has 4 GB of physical memory; the addresses needed to address memory, overlap the space needed for I/O devices. In this case, the need for I/O space takes precedence and the amount of memory visible to the operating system and applications is limited to 4 GB minus I/O space.
For more information, you can also refer to the below web link:
support.microsoft.com/.../978610
jackshack
6.4K Posts
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June 6th, 2012 18:00
Neal Miller;
Unfortunately, your Dimension 9150 uses the Intel 945 chipset which has a hardware limit of 4 GB of RAM. In order for a 64 bit operating system to make use of the entire 4 GB of RAM you have installed, the computer and operating system must support re-mapping of the RAM hidden by the reserved space to addresses above the 4 GB address space. One of the requirements that must be met for this to happen is that the chipset must have a capability of handling more than 4 GB of RAM. An example would be the Intel 965 chipset found in the Dimension 9200 which can handle 8 GB of RAM.
jackshack
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June 6th, 2012 20:00
No one is intentionally misleading anyone, but sometimes it's difficult to get the complete story. This page on the Microsoft site gives the situation in a manner more explicit than the link that was provided earlier:
http://support.microsoft.com/kb/929605
notLefty
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June 6th, 2012 14:00
that is the standard... anyone who puts in 4 gets about 3,5. it goes to the operating system and GPU. ...always...
Neal Miller
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June 6th, 2012 15:00
I don't believe this is the case... When I bring up Windows Task Manager, and I review the Physical Memory under the Performance tab, the "Total" memory is "3582." It is from that total that the OS, etc. consume their respective portions.
By the same token, our other computer has 9GB RAM. And the "Total" memory is "9206" which is what I'd expect.
Davet50
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14.4K Posts
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June 6th, 2012 16:00
is your other computer running a 64 bit OS? Any 32 bit system wil,l like previously mentioned, exhibit the same memory allocation. There is nothing you can do about it. It is the way the system allocation is programed.
Seydon
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June 6th, 2012 18:00
The difference might be the graphic card. I guess you other computer has an add-on card (nVidia? AMD?) while this one has an integrated one (Intel). Usually, integrated graphic cards will reserve memory for itself. That memory won't be available for the operating system...
Neal Miller
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June 6th, 2012 19:00
Many thanks for the information. I've checked, and the BIOS reports the full 4GB, while Windows "recognizes" all four gigs, but states that only 3.5GB are usable, both in System Information, and in Task Manager / Performance / Total Physical Memory.
Prior to the upgrade, when the same system had only 2GB, both the BIOS and Windows accurately reported the 2GB total. Presumably, I/O space applied then as well... Based on what you claim, shouldn't Windows have listed it as "2.00 GB (1.50GB usable)"
In other words:
Before Upgrade:
* BIOS: 2GB
* System Information: 2.00GB
* Task Manager / Performance / Total Physical Memory: 2GB (NOT compromised due to I/O space)
After Upgrade:
* BIOS: 4GB
* System Information: 4.00GB (3.50 GB usable)
* Task Manager / Performance / Total Physical Memory: 3.58GB (compromised due to I/O space)
Neal Miller
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June 6th, 2012 19:00
Ah.... So even though the motherboard is spec'ed at a 4GB max limit, there is no possible way that it can actually support 4GB? That seems a bit misleading.
Neal Miller
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June 6th, 2012 20:00
JackShank - Excellent link, thanks! I'm a little disappointed, but on the whole, I'm still looking at an upgrade gain of 1.5GB (2GB to 3.5GB), and when you factor in that the OS and other sundries normally consume about 1GB, my "free" RAM increased from 1.0GB to 2.5GB - a 150% increase.
Thank you again, all.