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ivanatora 12-09-2007 08:54 AM

Adding another 512MB RAM - not detected correctly?
 
Hello,
I already had one piece of 512MB DDR2 667MHz A-DATA RAM. I just bought another piece of 512MB DDR2 800MHz A-DATA and installed it. Both of these are running on 667MHz, becouse my motherboard don't support higher speeds.
In windows I see total 1GB of RAM. In `free`, I can see only that:
Code:

$ free -m
            total      used      free    shared    buffers    cached
Mem:          883        394        488          0          6        235
-/+ buffers/cache:        153        730
Swap:          454          0        454

GKrellm also shows 883MB total.
I'm unsure what is that about. I know it is possible to see a little bit undersize - for example yesterday `free` showed up about 480 instead of 512 RAM. But if even that is the case (about 40MB missing on each piece) `free` should print about 950MB.
Any suggestions?

RobertP 12-09-2007 09:14 AM

It could be an issue with the different speeds or the mobo and the kernel not talking...


Try running memtest86. It has a probe memory function and it gives other information about memory. It may show up in the grub menu if you install the memtest or memtest86 package.

Another possible interaction is with the graphics processor. Some use RAM for stuff. Check the Xorg driver you use.

Try editing the grub boot kernel option

append mem=1024M or whatever you can without getting a kernel panic. You can do that from the grub menu by typing e, editing and then b for booting. When you are satisfied, edit /etc/boot/grub/menu.lst

ivanatora 12-09-2007 09:33 AM

I'm using external video card (but my mobo has integrated one, too).
I use Lilo instead of GRUB, but I think there is similar appendable option. I'll check.
Thanks.

HappyTux 12-09-2007 11:49 AM

Quote:

Originally Posted by ivanatora (Post 2984917)
Hello,
I already had one piece of 512MB DDR2 667MHz A-DATA RAM. I just bought another piece of 512MB DDR2 800MHz A-DATA and installed it. Both of these are running on 667MHz, becouse my motherboard don't support higher speeds.
In windows I see total 1GB of RAM. In `free`, I can see only that:
Code:

$ free -m
            total      used      free    shared    buffers    cached
Mem:          883        394        488          0          6        235
-/+ buffers/cache:        153        730
Swap:          454          0        454

GKrellm also shows 883MB total.
I'm unsure what is that about. I know it is possible to see a little bit undersize - for example yesterday `free` showed up about 480 instead of 512 RAM. But if even that is the case (about 40MB missing on each piece) `free` should print about 950MB.
Any suggestions?

Aside from the onboard video probably taking some of the ram (you should see if it can be disabled) it looks like you have a 32bit kernel installed without the 1gb lowmem patch included in it, without it you need to use a kernel with highmem enabled to get your entire 1gb of ram seen/used. So check to see if can get a newer kernel to install or one with highmem enabled.

ivanatora 12-09-2007 01:39 PM

The onboard video is disabled.
I thought the highmem option is for more than 4 GB RAM? Do I need it for 1GB?

H_TeXMeX_H 12-09-2007 02:04 PM

Quote:

Originally Posted by ivanatora (Post 2985144)
I thought the highmem option is for more than 4 GB RAM? Do I need it for 1GB?

Yes, you do need highmem on for 1 GB or you'll got approx 880 MB instead.

HappyTux 12-09-2007 02:13 PM

Quote:

Originally Posted by ivanatora (Post 2985144)
The onboard video is disabled.
I thought the highmem option is for more than 4 GB RAM? Do I need it for 1GB?

You need highmem if you want all of it to be used up to 4gb even then you usually lose about .5gb due to memory mapping issues on 32bit so you have about ~3.5gb useable then over 4gb you need hugemem if I remember it corrected a couple of links below.

http://kerneltrap.org/node/6067
http://gentoo-wiki.com/FAQ_Linux_Mem...B_limit_on_x86


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