Problem using 4gb in 64 bits

[Ajulian]

Hello guys !

I have 4gb ddr2 in my computer, but the system shows something weird

It says that i have 4gb, but only 3gb usable...
I'm using a GA-945GCM-S2C motheboard that supports the 4gb

anyone knows a solution for this?

thanks !

 

[Reckon]

Hello, could you please make a screenshot of your system properties showing that?


thanks

 

[Ajulian]

Sure my friend

here the screenshot from my system properties

 

[Reckon]

Thanks for the info. I already reported this bug to Microsoft, but I didn't take any screenshot of my system properties dialog box when I saw that. I've been unable to reproduce it again. If you don't mind, I'm sending your screenshot to them.

Before solving the problem, could you check in the Task Manager your available RAM and post another screenshot here, please?

To solve your issue, just set PAE as ForceEnable in the BCDEdit. It may sound weird, but it was the only thing worked for me. In accordance to MS, the Physical Address Extension only works for 32 bits version of Windows, but... worked for me in W7 x64 RC. Something might be wrong there.

If you don't know how, open a cmd prompt (admin rights), type bcdedit.exe /SET PAE ForceEnable and reboot.

You should see then in both places, system properties and in the Task Manager your 4 gigabytes available.

Regards.

 

[Ajulian]

Hi Reckon,
Good morning and thanks for the help.

So, this is a bug?
the main reason for me to get 64 bits version was that i have those 4gb that i cant use in 32 bits.

Im working now, but when i get home i'll try to do that.
After you post i was reading about that command that you told me to use...he will force my PC to "see" the 4gb right ? but...really works in 64 bits? i was reading that this is for 32 bits version, as you say in your comment too...if it works, is another bug? hehe a god bug, i guess

Anyway
I hope it works !^^
i will let you know in this topic

And sure, you can send this screenshot
thanks for the help

(and sorry for my english )

 

[Uber Philf]

Hey guys, im having the exact same problem, just that mine displays 2.97gb usable.
I tried what Reckon said, and it hasn't changed at all, it still displays 2.97gb , any other solutions?

Enzo.

 

[Ajulian]

When I begin to search a solution for this problem, I heard once that update the BIOS may help, but I never tried
May be a solution...i dont know...
I’ll try this too if Reckon says doesn’t work for me

 

[Reckon]

Try to look at any remapping memory options in the BIOS.

Regards

 

[Reckon]

Hey guys, im having the exact same problem, just that mine displays 2.97gb usable.
I tried what Reckon said, and it hasn't changed at all, it still displays 2.97gb , any other solutions?

Enzo.

Enzo, could you please post a screenshot of your system properties window? Also, could you check available memory in the task bar?

Thanks

 

[Uber Philf]

yeahp here :

 

[baarod]

That's video card shared memory folks.

 

[Uber Philf]

Dangit, i only got 512mb Graphics? Why is it taking up 1.03gb?

Enzo.

 

[Ajulian]

Dangit, i only got 512mb Graphics? Why is it taking up 1.03gb?

Enzo.

Same here
i have 512 in my video card too

 

[baarod]

This is written for Vista64 but mostly applies to 7 as well: The system memory that is reported in the System Information dialog box in Windows Vista is less than you expect if 4 GB of RAM is installed

 

[Reckon]

This is written for Vista64 but mostly applies to 7 as well: The system memory that is reported in the System Information dialog box in Windows Vista is less than you expect if 4 GB of RAM is installed

That's for 32 bits version of Windows?

 

[Reckon]

That's video card shared memory folks.

This is true if you own a GPU incorporated in the motherboard and you are sharing memory. If you do own a GPU, that's not what Windows should be reporting.

 

[baarod]

This is true if you own a GPU incorporated in the motherboard and you are sharing memory. If you do own a GPU, that's not what Windows should be reporting.

Read the KB. It specifically states that video memory must be mapped into addressable memory. AGP used to call it an aperture.

 

[baarod]

That's for 32 bits version of Windows?

From the KB:

APPLIES TO

• Windows Vista Business
• Windows Vista Enterprise
• Windows Vista Home Basic
• Windows Vista Home Premium
• Windows Vista Starter
• Windows Vista Ultimate
• Windows Vista Enterprise 64-bit Edition
• Windows Vista Home Basic 64-bit Edition
• Windows Vista Home Premium 64-bit Edition
• Windows Vista Ultimate 64-bit Edition
• Windows Vista Business 64-bit Edition

 

[Ajulian]

So, i can't disable this sharing memory and have all my 4gb running separate from my video card?

 

[brucemoose2]

So, i can't disable this sharing memory and have all my 4gb running separate from my video card?

Let me start by saying that the Microsoft support document referenced above is a great resource and explains this issue well. I will assume that you've read that article and still have questions, so let me rephrase this for you here.

1. Memory addresses below 4GB are a finite resource and there is competition for those addresses. Some of them are reserved for the system firmware/BIOS, then some for devices (see number 2), and the leftover addresses are used by Windows.

2. PCI configuration space is memory-mapped (meaning that it's accessed in the same manner and using the same addressing scheme as physical memory) and typically consumes address space below 4GB for 32-bit OS compatibility reasons. Addresses used for PCI configuration space cannot be used by the OS to access physical memory. To use a simple analogy: Windows cannot park any cars (data) in those parking spots (addresses) because someone else (a device) is already parked there.

3. Each device in your computer consumes a small part of the PCI configuration space below 4GB. This is true regardless of whether you have an on-board video card or an add-in card.

4. If your system BIOS does not support memory remapping then there is no way for Windows to utilize the physical memory whose addresses are overlapped by PCI configuration space without corrupting PCI device state in the process.

So, in summary: If you install 4GB of memory in your computer that is running a 64-bit version of Windows and you do not know how or do not have a mechanism to enable memory remapping (this would be an option in the system BIOS, if it were available), the firmware will consume a few MB of memory and PCI configuration space will overlap a much larger block of memory (typically between 512MB and 1GB) and you will be left with approximately 3 to 3.5GB of RAM. This is not a bug in Windows. In fact, Windows is doing exactly the right thing because it's not corrupting your device state.

*Note: If you don't have an option to enable memory remapping and you think that your system should support it, you might try loading a newer system BIOS or contacting your system manufacturer or motherboard vendor to request a system BIOS update with memory remapping support.