64-bit doesn't show 4GB RAM
 

Hi,

I'm using a 64-bit release. But, my PC doesn't seem to show the full 4GB of RAM that is installed. It shows about 3.4 to 3.6GB of RAM (please see attached picture).

I thought that if I could install a 64-bit OS that would mean that I have a 64-bit capable processor. I thought using a 64-bit release would show all 4GB or RAM on my PC.

What am I doing wrong? My CPU is a Pentium 4 Prescott DT 630.

More information on my system is below:
Thank you for your time and help.

The problem is in either the motherboard or the BIOS, not in the OS.

This is discussed in many other threads at LQ.

If it is not a motherboard issue, there is likely a BIOS setting that can be changed to fix the problem. But the details vary a lot by BIOS version, so it would be hard to guide you to the correct BIOS setting even if it exists.

Detailed motherboard info, or better yet a link to an online copy of the motherboard manual, would make it easier for someone to help you.

Some related threads:

Here the OP started by looking in many of the right places to verify that what is usually a BIOS or motherboard issue actually was. In the unusual case shown in that thread, the problem actually wasn't BIOS/Motherboard:
http://www.linuxquestions.org/questi...6/#post4313393

This thread touches on two of the common topics within this issue: Ram used by the integrated graphics, and motherboard specs claiming to support 4GiB when they really support slightly less. I don't see a clear final answer in this thread:
http://www.linuxquestions.org/questi...my-ram-867990/

Here is one of the (unfortunately unusual) cases in which someone I encouraged to look for the setting in his BIOS not only found it, but also reported back to the thread what he found:
http://www.linuxquestions.org/questi...2/#post3150066

may or may not help

you have a AMD 64 bit kernel for a INTEL cpu ???????

"AMD64", in most cases, simply refers to the x86_64 architecture, whether the chip itself is made by AMD, Intel, or some other manufacturer…

Also, if this is the OP's CPU, then it indeed has 64-bit capability. It's doubtful the 32/64-bit difference has anything to do with this problem, though, as theoretically even a 32-bit kernel can address 4 GiB of memory.

Thanks.

I didn't know that the motherboard might be the issue. Below is the output of dmidecode and it indicates "Maximum Capacity: 4 GB"

Output from dmidecode:
Output from dmesg | grep BIOS:
Below is output from cat /proc/iomem:
I have no ability to alter RAM via BIOS on this PC.

That usually means the max usable ram is significantly lower than 4GB (typically around 3.5GB) and there is nothing the OS can do about it.

It is still possible there is some BIOS setting to let you use significantly closer to 4GB than is now usable. But it isn't very likely.

That unambiguously shows the problem is either motherboard or BIOS and not Linux. I assumed that from the start in this thread, but this confirms that assumption.

That setting would not be in the ram or memory section of the BIOS menu. If it exists, it would be confusingly located and named.

But more likely it isn't there and you can't enable more ram than you now have.

OK. Thanks for clearing that up for me.