Kernel for i686 which uses all 4GB RAM?

Joffer · 2007-12-08 03:24:47

I've got i686 (x86) version of Arch installed. How can I make it use all my 4GB RAM? It just sees 3,3GB now. I know it's possible to use more than 4GB on 32-bit with some tweaks etc (I'm using 8GB on RHEL i386 servers at work), but how do I make it so in Arch?

[joffer@armor ~]$ free
             total       used       free     shared    buffers     cached
Mem:       3369468    3244168     125300          0      11812    2955268
-/+ buffers/cache:     277088    3092380
Swap:      4064404          8    4064396

kishd · 2007-12-08 03:54:53

You would have to recompile the kernel and enable Config_highmem64g. This enables PAE (physical address extension) which allows the kernel to see all the ram.

lilsirecho · 2007-12-08 04:06:43

Please excuse my intrusion, but how can an X86 mobo operate with PAE if it isn't built into the mobo cpu?

iBertus · 2007-12-08 04:46:49

PAE is a feature of many 32-bit CPUs as I believe that it was originally intended to allow these CPUs to address larger memory spaces.

lilsirecho · 2007-12-08 07:05:36

True Ibertus but not apparent from the post.

An added observation is that the added PAE requires ram for addressing so the full 4GB is not accessible, about 3.5GB is useable. Thusly, the added 1GB is actually only a half GB and requires the 64g highmem mod to the kernel..required for every new upgrade.

Joffer · 2007-12-08 10:30:57

My system is a Q6600+P35 if it helps.

Arch Linux

#1 2007-12-08 03:24:47

Kernel for i686 which uses all 4GB RAM?

#2 2007-12-08 03:54:53

Re: Kernel for i686 which uses all 4GB RAM?

#3 2007-12-08 04:06:43

Re: Kernel for i686 which uses all 4GB RAM?

#4 2007-12-08 04:46:49

Re: Kernel for i686 which uses all 4GB RAM?

#5 2007-12-08 07:05:36

Re: Kernel for i686 which uses all 4GB RAM?

#6 2007-12-08 10:30:57

Re: Kernel for i686 which uses all 4GB RAM?

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