Macbook Pro recognize only 3 GB of RAM

ganja_guru · 2008-10-03 17:49:15

Hi guys, I have arch64 installed on my MBP with 4 GB of ram. All of the RAM was recognized in OSX, but Linux only recognizes 3 GB. The output of "free -m" is:

total used free shared buffers cached
Mem: 3003 869 2134 0 61 462
-/+ buffers/cache: 344 2658
Swap: 0 0 0

I checked with openSUSE and Ubuntu(though both were i686), and both of them also report only 3 GB of RAM. I remember the kernel having the HIGHMEM=64GB option, but this seems to have been dropped somewhere along the way (or maybe this option does not apply to 64bit Kernels). Any ideas? Are your 4GB laptops/desktops reporting all of your ram? What about your 8GB boxes? what do they report?

Thanks in advance.

Last edited by ganja_guru (2008-10-03 18:19:32)

Dieter@be · 2008-10-04 12:47:09

Can you post the output of dmesg? (and btw, did you get sound working? see http://bbs.archlinux.org/viewtopic.php?id=39765 )

ganja_guru · 2008-10-04 13:18:57

Getting sound to work was easy, I just had to make sure my User was in the audio group. I didn't have to change anything else. This is the output of dmesg:
http://www.pastebin.ca/1218877

miguimon · 2008-10-04 22:18:27

I upgraded my MB 3.1 Santa Rosa to 4GB thinking that my arch (686 install) could handle all the memory but at the end it just recognises 3GB. Obviously, now I know why.. So I wanted to switch to arch64 and see how it goes but I would like to be sure that it will work. free -m output:

total used free shared buffers cached
Mem: 2999 1474 1525 0 85 948
-/+ buffers/cache: 440 2559
Swap: 4089 0 4089

and my dmesg output:
http://www.pastebin.ca/1219310

ganja_guru · 2008-10-08 03:55:20

why don't you just pop the arch64 installation cd in and check the memory from the setup prompt?

ganja_guru · 2008-10-11 19:35:44

does anyone have 4GB/8GB fully recognized by arch?

ganja_guru · 2008-10-22 04:54:52

bump

syscrash2k · 2008-10-26 23:50:47

I have 4 gigs of ram working fine on my R61, and 8 gigs on my desktop.

cactus · 2008-10-27 06:15:06

ganja_guru wrote:

Hi guys, I have arch64 installed on my MBP with 4 GB of ram. All of the RAM was recognized in OSX, but Linux only recognizes 3 GB. The output of "free -m" is:
total used free shared buffers cached
Mem: 3003 869 2134 0 61 462
-/+ buffers/cache: 344 2658
Swap: 0 0 0
I checked with openSUSE and Ubuntu(though both were i686), and both of them also report only 3 GB of RAM. I remember the kernel having the HIGHMEM=64GB option, but this seems to have been dropped somewhere along the way (or maybe this option does not apply to 64bit Kernels). Any ideas? Are your 4GB laptops/desktops reporting all of your ram? What about your 8GB boxes? what do they report?
Thanks in advance.

the HIGHMEM setting (which effectively requires PAE) does not apply to 64 bit.
ubuntu 32 bit does not have the highmem 64 enabled by default. you have to install the -server kernel for that if I recall.
No clue about SuSE.

It does seem odd that arch64 is not seeing all the ram though.
*head scratching*

byte · 2008-10-27 07:50:02

Using 64-bit systems will give you access to all your RAM, quite simple. (err... no idea what's up with Macs)
To use my 4GB on 32-bit systems I'd have to enable the Memory Remap feature in BIOS and use a PAE-enabled (HIGHMEM64G) kernel.

Last edited by byte (2008-10-27 07:53:50)

Arch Linux

#1 2008-10-03 17:49:15

Macbook Pro recognize only 3 GB of RAM

#2 2008-10-04 12:47:09

Re: Macbook Pro recognize only 3 GB of RAM

#3 2008-10-04 13:18:57

Re: Macbook Pro recognize only 3 GB of RAM

#4 2008-10-04 22:18:27

Re: Macbook Pro recognize only 3 GB of RAM

#5 2008-10-08 03:55:20

Re: Macbook Pro recognize only 3 GB of RAM

#6 2008-10-11 19:35:44

Re: Macbook Pro recognize only 3 GB of RAM

#7 2008-10-22 04:54:52

Re: Macbook Pro recognize only 3 GB of RAM

#8 2008-10-26 23:50:47

Re: Macbook Pro recognize only 3 GB of RAM

#9 2008-10-27 06:15:06

Re: Macbook Pro recognize only 3 GB of RAM

#10 2008-10-27 07:50:02

Re: Macbook Pro recognize only 3 GB of RAM

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