Arch Linux

professor_b

Member

Registered: 2007-05-24

Posts: 8

all memory not recognized

I have 4G ram installed. The BIOS sees all 4G, says all 4 are available. Arch only sees 3G's worth. I'm running kernel 2.6.21-viper. I migrated from Ubuntu a while back, and Ubuntu saw it all. Any thoughts on how I can get back my extra gig?

retsaw

Member

From: London, UK

Registered: 2005-03-22

Posts: 132

Re: all memory not recognized

I think the default kernel should support 4G.  Perhaps adding the option "mem=4096M" to your kernel command line in your bootloader will let you use all your RAM.

[vEX]

Member

From: Sweden

Registered: 2006-11-23

Posts: 450

Re: all memory not recognized

Interesting, I got 2GB RAM and Linux only sees 2012MB instead of 2048MB. Using Arch64 and 64-bit kernel and no clue how to make it see the rest. :-/

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Login_Here

Member

Registered: 2007-06-27

Posts: 24

Re: all memory not recognized

Same here, I've got 4GB RAM, High Memory Support enabled in the kernel, and Linux (or at least Arch, I haven't tried any other distribution on this computer) only sees about 3,6GB.

kishd

Member

Registered: 2006-06-14

Posts: 401

Re: all memory not recognized

I have 4G ram on an Asus P5B VM board. The bios sees all 4G. However for arch to see all the ram I had to recompile the kernel with mem=64G option to turn on PAE (physical address extension). It may just be because of the design of the motherboard that this was needed.

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professor_b

Member

Registered: 2007-05-24

Posts: 8

Re: all memory not recognized

Some motherboards can't see all 4G. For example, on Ubuntu with my Asus A8N5x, it saw about 3.6GB because of what the motherboard manual calls "chipset resource allocation." I'm not even getting this much with Arch, though.

Thanks for the tips. I'll try a recompilation and some kernel line parameters.

quetzyg

Member

From: /home/quetzyg

Registered: 2006-08-03

Posts: 130

Re: all memory not recognized

Maybe it's not a Linux problem, but a BIOS problem (an old one, for that matter).
Although the BIOS can detect the whole 4GB of ram installed, it just uses part of it.
It happened to me with my ASUS M2N32-SLi Deluxe, when using a factory default BIOS.

I got the latest one, flashed the bastard, and all the RAM can now be used!

Hope it helps

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