I have 4GB of RAM and only 2.8 is showing. P5B-VM

[Hilob101]

I have an Asus P5B-VM with an Intel Core 2 Duo processor. I have 4x1GB of OCZ 800MHz memory installed in my system. Only 2.8GB of memory is showing when the system boots, as well as in the operating system. I can try any two chips of memory, and it will show 2GB of RAM, so I know it's not a defective chip. I am running the latest BIOS revision (405).

If anybody can provide some suggestions on how I can get all 4GB detected properly, it would be most appreciated.

Thanks!

[Sheppard]

32bit can only address 4gb of ram in total, if you have virtual memory it will only show the difference in your real ram, try turning virtual memory down and see what happens.

[Hilob101]

I figured it out. For anyone else who runs into this issue, here is what you do to fix it:

1. Go to the BIOS

2. Go to Advanced -> Chipset -> North Bridge Configuration

3. Change Memory Remap Feature from Disabled to Enabled.

The system now sees all 4GB of memory.

I am not sure what this memory remap feature does, except take over a 1GB of memory...

[Puggsley]

This feature allows the system to address more memory than the normal limit of 32bit OS

[Hilob101]

This feature allows the system to address more memory than the normal limit of 32bit OS

I'm running a 32 bit OS however (Linux), and it shows all 4GB of memory now. I have a Core 2 Duo Processor, so I suppose I could install the 64 bit version, but I did not see the need. Shouldn't I be able to use all 4GB?

[serious]

You are able to access 4GB of RAM, even with a 32bit system, now since you tuned it in i BIOS. No need to change

[Randolph]

Can I ask: what do you do that needs 4GB? Thats alot. :huh:

[+Nik Louch Subscriber²]

Can I ask: what do you do that needs 4GB? Thats alot.

Large video editing, massive phot editing, hi-res page layout - just 3 reasons why a user would need a lot of memory.

[Randolph]

Large video editing, massive phot editing, hi-res page layout - just 3 reasons why a user would need a lot of memory.

Oh thanks!

[Elliot B.]

Large video editing, massive phot editing, hi-res page layout - just 3 reasons why a user would need a lot of memory.

Video editing maybe, but the other two? :|

[Sethos]

I figured it out. For anyone else who runs into this issue, here is what you do to fix it:

1. Go to the BIOS

2. Go to Advanced -> Chipset -> North Bridge Configuration

3. Change Memory Remap Feature from Disabled to Enabled.

The system now sees all 4GB of memory.

I am not sure what this memory remap feature does, except take over a 1GB of memory...

Now it went from 2,5gb to just 2gb ...

[chrismaddern]

Video editing maybe, but the other two? :|

There are photoshop effects that if run on large images can take approaching a full waking day, so more memory means a quicker execution :D. Always worth it :D:D

(Yes.. I know processor is often the limitation here, but every little.....)

Chris

[Raa]

Agreed, 4gb of ram IS useful for a number of applications.

I'm upgrading to 3gb of ram soon coz I do a few tasks like that.

I wont be using a 64bit o/s. So I should see most of my ram ;)

The reason you're not seeing your "full 4gb" of ram is because of 32bit pci address space allocation. This is a physical limitation of the 32 bit pci system when used with a 32 bit o/s. This means ANY 32 bit o/s of Windows (Including Vista), Linux may also be affected, but I really dont know.

You might HAVE 4gb of ram, but the ADDRESS SPACE is being used by pci devices in your system. (this also includes video cards on AGP or any PCI/E devices etc)

If you have a SLI setup of 2 x 512 mb cards, you've wiped off 1gb of your ram's addressable space already before you start adding the other devices in. This address space is allocated in "top-down" order, starting from the 4gb boundary and counting down until all devices have had space allocated.

There ARE ways around this, 64bit o/s is one choice - not my favorite or you can use Virtual Addressing. This also isn't 100% compatible with everything either, so you might want to experiment with it first.

You can check this out at Microsoft's support site, doing a search for "4gb ram" I think should work. A MS KB Article here for some information.

Now you can see why I stuck to 3gb of ram for now ;)

Edited December 12, 2006 by Raa

[koppit]

would a mac make any difference now that they're running on intel hardware instead of powerpc chips now?

[Japlabot]

would a mac make any difference now that they're running on intel hardware instead of powerpc chips now?

You should clarify the question, but an Apple PC would have the same limitations of a non-Apple PC with the same CPU. They use exactly the same hardware/architecture as other PCs. The only difference is the default Operating System (Mac OS X compared to Windows or Linux)

[Hilob101]

Can I ask: what do you do that needs 4GB? Thats alot. :huh:

This box is a 1U server. Databases and lots and lots of apache instances is what I'll need it for :)