I added up to 4GB of memory(4 sockets of 1GB). Why it only reads 3.50GB of RAM?

Question

My computer is Compaq Presario. I found out that it could add up to 4gb of RAM but when I installed 4GB of RAM, it only reads 3.50! Why? Thank you.

Answer 1

I found this snippet related to your issue:

Recently I assembled a new computer with 4GB RAM. My motherboard supports up to 8GB RAM and Widows XP supports 4GB RAM so no problem.....

But when I open the System Properties, it shows only 3.23GB of RAM. Where did the rest go? OK, I'm using onboard VGA with 256MB memory, so part of the RAM will be allocated to that and will not be shown in System Properties. But even with that there is considerable amount of RAM is missing.

4GB RAM not showing in System Properties.

I wanted to know why it is. So I did an Google search and found out this. Reason is XP uses its 32bit address space not only to address memory but also to address some other components like System ROM , APIC(s),Integrated PCI devices, such as network connectors and SCSI controllers, PCI cards , Graphics card, etc... Because of this some part of the ram may not be accessible by the operating system since it ran out of address space.  

Answer 2

Windows 32-Bit can only recognize 3.5 GB of RAM, that includes your video card.  That last .5 GB is unused, you've basically pushed your system to the limit the OS can handle.

Answer 3

It's because it allocates some of the Memory to other parts of you're PC to Boot up and help it work.

It's the same in all PCs,..my 1GB of Ram doesn't show that on my system,..it shows:896mb instead.

The same goes for my Maxtor External Hardrive.Its a 320GB,but it shows 298GB's instead.

The same also goes for my Hardrive(c:\) it's a rubbish 120GB but shows 107GB instead,which is even worse!

Why do you think i got an external to help out my main hardrive,it's too much pressure on the system with all the stuff i've got on it.

I am looking for a better PC and i'll probably sell this one on,..or give it to a relative,..as it's fine for a young Child's room.

So don't worry that you aren't seeing the full amount,..it's very normal! ;)

Answer 4

It could be that you are running a 32-bit operating system such as Windows XP or the 32-bit version of Vista.  Without more details it is hard to say for sure.  I would bet it's the version of windows you are running.  Here is a link that explains it better.

http://blogs.msdn.com/hiltonl/archive/20...

Answer 5

It is possible that your mother board will only support 3.5GB of RAM, if this is the problem then it will only read that amount. Where did you get the information on the amount you could add? Check with your motherboard manufacturer for specifications on the board. Most have websites. If you are sure that it will support 4 GB then you might have a defective stick of RAM. Hope this helps!

Answer 6

You say "it only reads 3.5" but you don't say what the "it" is. The answer is completely different if the "it" is the BIOS memory size screen than if it's the Windows system information panel.

If it's the BIOS memory size screen, it is because your BIOS is configured for a 32-bit OS. If you have a 32-bit OS, everything is fine. If you have a 64-bit OS, you need to set the BIOS for this. The option is often called 'memory remapping'. Turn it *on*.

Note that if you have a 32-bit OS and memory remapping is on, you may be able to get a bit more usable memory by turning it *off*. But I doubt this, as usable memory with remapping off on a 32-bit OS is usually less than 3.5 GB.

If you have a 32-bit OS, the answer to your question is that a 32-bit OS can only address 4GB and things other than your RAM take up some of that space.

If you have a 64-bit OS, the answer is that memory remapping is off in your BIOS, and the BIOS is trying to get as much memory below 4GB as possible to let a 32-bit OS use as much memory as possible, which renders it inaccessible to a 64-bit OS.

Summary:

64-bit OS -> Turn remapping on. You should get all 4GB.

32-bit OS -> Turn remapping off. You will get as much as possible, usually 3.2 to 3.6GB.

Answer 7

It is because you are probably running a 32-bit operating system, so no matter how much RAM you add, it will always show the 3.5GB.

Answer 8

Maybe your VGA has a shared ram