not getting full use of RAM on P5GC-MX133 2

[stfaprc]

Intel Pentium Dual CPU E2160
2 2-Gig DDR2 sticks installed.

The BIOS reports
System Memory 4096
Approbiated 648
Available 3448

there is onboard graphics taking up 8M + 128M for the DVMT.

What is going on with the "Approbiated"? What is it and why is it taking up so much RAM?

 

[kmcferrin]

You will never get the full 4GB of RAM on a 32-bit Windows installation because of the way that memory is used. What you are seeing is (more or less) normal and correct for 32-bit Windows systems with 4GB of RAM installed.

From your 4096 MB installed you will lose not only the shared memory for the video card, but you also lose roughly 512MB for memory mapped devices as well. I'm not sure about the terminology that the BIOS is using, but that's what's happening.

Now if your BIOS has an option that you can set to enable a 64-bit OS (I've seen a few that do) then it might change the way that it is using/reporting memory.

________________________________________
CompTIA A+, Network+, Server+, Security+
MCTS:Windows 7
MCTS:Hyper-V
MCTS:System Center Virtual Machine Manager
MCSE:Security 2003
MCITP:Enterprise Administrator

 

[stfaprc]

hi,
well I'm looking at the BIOS setup screen itself, not the OS (but see next paragraph).
In the BIOS the closest thing I could see to 64bit OS option was to turn on the 'Plug & Play' OS option.
it didn't see to make a difference.

The OS is CentOS5.4 Linux 2.6.18-164.9.1.el5xen on x86_64.
There is an error/warning message that shows up when it starts up, "PCI: not using MMCONFIG" - is that related to the RAM?

Is there any real benefit in running this pc with 4G of RAM or should i go with 1 2G stick and 1 1G stick? or just go back to the original 2 1G sticks?

thanks.

 

[Nelviticus]

The BIOS setting can be called pretty much anything - on my old Asus motherboard it was called 'memory remap' and if it was set to 'off', a 32-bit OS could see about 3.5GB out of 4GB and a 64-bit OS could only see 2GB. If it was set to 'on', things were the other way around - 64-bit OS could see all 4GB but the 32-bit OS could only see 2GB. On my current motherboard I don't have to set anything at all - both OS's can see as much as they can use.

Is there any real benefit to using 4GB? It depends what you're doing. If you're editing video or working with very large images then yes. Otherwise probably no.

Regarding the 'PCI: not using MMCONFIG' message, according to post #4 in this thread it's because of a bug in your BIOS. It's not fatal and the OS just works around it but you may want to find out if there's a newer BIOS version available.

Regards

Nelviticus

 

[kmcferrin]

As far as there being any benefit, it does depend on what you're doing but generally having more memory is advantageous. If faced with the choice between having 2GB installed, 3GB installed, or 4GB installed (but only being able to use 3.5GB of it) I would go with the full 4GB. The system still makes use of that memory even if it isn't directly available to your applications.

________________________________________
CompTIA A+, Network+, Server+, Security+
MCTS:Windows 7
MCTS:Hyper-V
MCTS:System Center Virtual Machine Manager
MCSE:Security 2003
MCITP:Enterprise Administrator