Installed 4gb of RAM memory, but BIOS says only 2.5gb are usable

Hi.
I recently brought a memory upgrade for my nice old computer, to upgrade it to 4gb. (I bought two 2Gb memory crads)
The BIOS (as well as the OS) recognize that I have 4gb RAM installed, but list only 2.5gb as usable! :pfff:

I want to be clear- this is not an OS problem. I'm runnning Windows 7 Ultimate x64. And the problem starts at the BIOS level.

I've done a lot of research, it I think the problem might be that my motherboard's chipset will use part of the memory address for other uses- such as graphics card memory, and BIOS memory and so forth, but I don't think this should add up to 1.5 gigs!

Please help me...
Here is my system spec:

Motherborad: ASUS P5VD2-MX
CPU: Intel Core2Duo 6300 @ 1.86GHz
Chipset (I think this is a chipset): VIA P4M890
Memory: 2X Kingston 2GB (for a total of 4GB) DDR2 533, PC2-4300
Graphics: Nvidia Quadro FX 570, 256Mb
Sound: Sound Blaster Audigy
PCI expansion card for 4xUSB and 3XFirewire 400
2xSATA drives
DVD Burner
OS: Windows 7 Ultimate x64

Thank You

Message quoted 1 times

Reply to er_ouz

Ok i do not no the exact name of the option in bios but i think there is something called memory configuration protection.that limits ur memory see if that works

Reply to dayto11

Hi, I'm affraid I didn't see any such option or anything remotley simillar to it.
I scoured through the BIOS settings, read the manual (which was useless), upgraded the BIOS to the latest version... Nothing there...

The bios is Phoenix-AwardsCMOS BIOS, the update is 1017.which was released in 2007...
http://support.asus.com/Download.a [...] &p=1&os=25

Any other ideas? Anybody? I'd really appreciate any help on this...

Reply to er_ouz

Ok after doing some research it appears that ur board only supports up to 2gb so it is a board limitation

Message quoted 1 times

Reply to dayto11

dayto11 wrote :

Ok after doing some research it appears that ur board only supports up to 2gb so it is a board limitation

Thank you for your reply, though I'm not quite sure which sources you're going by. I don't think you're correct.

For one thing, the board shows I have 4 gigs installed, 2.5 of which are usable (so already more then the 2gb limit you suggested).

Secondly, the motherboard guide specifically says that the motherboard's limit is 4gigs:
Specifications: Memory: 2 x 240-pin DIMM sockets support up to 4 GB ofDDR2 533/400 unbufferred non-ECC memory

Source: Motherboard Guide (page 10)
http://dlcdnet.asus.com/pub/ASUS/m [...] update.pdf

Reply to er_ouz

my source was the asus website
http://www.asus.com/Motherboards/I [...] 5VD2MX_SE/

Message quoted 1 times

Reply to dayto11

dayto11 wrote :

my source was the asus website
http://www.asus.com/Motherboards/I [...] 5VD2MX_SE/

That's the wrong board. Mine is P5VD2-MX.
No "SE" at the end.
Here is the link:
http://www.asus.com/Motherboards/I [...] 5/P5VD2MX/

Message quoted 1 times

Reply to er_ouz

er_ouz wrote :

That's the wrong board. Mine is P5VD2-MX.
No "SE" at the end.
Here is the link:
http://www.asus.com/Motherboards/I [...] 5/P5VD2MX/

o i am very sorry about that could u maybe screen shot ur bios?
cause we know for a fact its not ur os we know its not ur dim slots becasue its reading the ram hmmmm it has to be something in the bios so thats my only idea
or maybe.... reset bios i dont know if that will help but thats my only idea other than listed above

Message quoted 1 times
Message edited by dayto11 on 12-12-2011 at 11:20:00 PM

Reply to dayto11

dayto11 wrote :

o i am very sorry about that could u maybe screen shot ur bios?
cause we know for a fact its not ur os we know its not ur dim slots becasue its reading the ram hmmmm it has to be something in the bios so thats my only idea
or maybe.... reset bios i dont know if that will help but thats my only idea other than listed above

Hi dayto11
The Bios was recently reset after a failed oveclocking attempt (this was before I installed the new memory, and I'm positive it's unrelated). It is also the latest BIOS update available from ASUS.
Here is a link to an ImageShack album with 11 screen shots from my BIOS. I wasn't able to find anything relevant in the BIOS myself:
http://imageshack.us/g/31/09122011236.jpg/

Reply to er_ouz

Ok after looking at the screen shots: top performance what does this do mabey try turning off? And another thing it says that just under 2 gigs is being used as cache i dont exactly know how to fix but mabey 1.5 gigs is being used by parts around ur system thats all i can think of sry i cant figure out the issue.

Reply to dayto11

er_ouz wrote :

Hi.
I recently brought a memory upgrade for my nice old computer, to upgrade it to 4gb. (I bought two 2Gb memory crads)
The BIOS (as well as the OS) recognize that I have 4gb RAM installed, but list only 2.5gb as usable! :pfff:

I want to be clear- this is not an OS problem. I'm runnning Windows 7 Ultimate x64. And the problem starts at the BIOS level.

I've done a lot of research, it I think the problem might be that my motherboard's chipset will use part of the memory address for other uses- such as graphics card memory, and BIOS memory and so forth, but I don't think this should add up to 1.5 gigs!

Please help me...
Here is my system spec:

Motherborad: ASUS P5VD2-MX
CPU: Intel Core2Duo 6300 @ 1.86GHz
Chipset (I think this is a chipset): VIA P4M890
Memory: 2X Kingston 2GB (for a total of 4GB) DDR2 533, PC2-4300
Graphics: Nvidia Quadro FX 570, 256Mb
Sound: Sound Blaster Audigy
PCI expansion card for 4xUSB and 3XFirewire 400
2xSATA drives
DVD Burner
OS: Windows 7 Ultimate x64

Thank You

Try reinserting/ change slots of the RAM. Mine has 2 1 gb RAM but BIOS and Windows reports it has only 1 gb. The first try of reseating the RAM, BIOS reported 1.5 gb. After changing slots, it now reports the full 2 gb.

Message quoted 1 times

Reply to joeysp

joeysp wrote :

Try reinserting/ change slots of the RAM. Mine has 2 1 gb RAM but BIOS and Windows reports it has only 1 gb. The first try of reseating the RAM, BIOS reported 1.5 gb. After changing slots, it now reports the full 2 gb.

I'll give it a try, even though they're both the same make and brand of memory cards, but at this point i'm not scuffing aany suggestions...
I'll tell you how it goes.
Thank you.

Message quoted 1 times

Reply to er_ouz

er_ouz wrote :

I'll give it a try, even though they're both the same make and brand of memory cards, but at this point i'm not scuffing aany suggestions...
I'll tell you how it goes.
Thank you.

Any update? I'm having the same issue.

Reply to quicks713

Didn't work.
Tried switching between the two memories, nothing happened.
Aslo tried removing PCI extension cards (Sound Blaster Audigy sound card and a USB/firewire card) with no difference in the ammount of usable memory shown on the BIOS.

Reply to er_ouz

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