Arch Linux

Lowra

Member

Registered: 2009-09-21

Posts: 192

Differences of RAM used with a config in 32 & 64bits OS

Hello,
I just would like to understand a thing: Does Archlinux 64bits really use more RAM than Archlinux 32bits ?
I've enough RAM, I'm using Openbox with pcmanfm but I saw that I use at leat 300MB of RAM while other Archers say that they use ~200 with other applications started like Chromium, and more daemons than me

It's just to understand, I've 4.0GB of RAM...

skottish

Forum Fellow

From: Here

Registered: 2006-06-16

Posts: 7,942

Re: Differences of RAM used with a config in 32 & 64bits OS

Hello,
I just would like to understand a thing: Does Archlinux 64bits really use more RAM than Archlinux 32bits ?
I've enough RAM, I'm using Openbox with pcmanfm but I saw that I use at leat 300MB of RAM while other Archers say that they use ~200 with other applications started like Chromium, and more daemons than me

It's just to understand, I've 4.0GB of RAM...

Yes, 64 bit systems by definition use significantly more RAM than 32 bit for the same tasks.

jmad980

Member

From: Califonia

Registered: 2010-03-11

Posts: 54

Re: Differences of RAM used with a config in 32 & 64bits OS

Yeah it uses a few bits more of ram (sorry for poor humor) I ended up on 64bit Arch, (I have 1.7GB of RAM) and it still takes effort to fill that up, its been awhile since i've been on 32bits, but from what I remeber a few things have been fairly faster with it I don't really see why not to if you have 4GB of ram, besides unused ram is wasted ram

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Someone call a doctor, my awesome configuration broke again! || To err is human -- to blame it on a computer is even more so.

skottish

Forum Fellow

From: Here

Registered: 2006-06-16

Posts: 7,942

Re: Differences of RAM used with a config in 32 & 64bits OS

There are some good wikipedia articles about 64 bit that will help shed some light. One thing of note: Somewhere between most to no desktop chips are purley 64 bit. For instance:

 ~ > grep address /proc/cpuinfo
address sizes    : 48 bits physical, 48 bits virtual
address sizes    : 48 bits physical, 48 bits virtual
address sizes    : 48 bits physical, 48 bits virtual
address sizes    : 48 bits physical, 48 bits virtual

Phenom II 955 (quad-core, of course) is 48 bit in some ways and 64 in others.

demian

Member

From: Frankfurt, Germany

Registered: 2009-05-06

Posts: 709

Re: Differences of RAM used with a config in 32 & 64bits OS

on my very subjective test i noticed that on 64bit ArchLinux my 4GB fill much quicker than my 3GB with 32bit ArchLinux. Other than with 32bit, on 64bit the RAM often got completely filled, too. And since i had no swap partition, the system started to feel sluggish.
Because of some other annoyances I'm back to 32bit with swap (though not used) and i'm very happy with the ram usage.

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no place like /home
github

jac

Member

From: /home/jac

Registered: 2009-05-19

Posts: 431

Website

Re: Differences of RAM used with a config in 32 & 64bits OS

@skottish: Why, you just blew my mind. Mine is 36 physical/48 virtual. Thank you for the eye opener, I will definitely research this more now

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: Differences of RAM used with a config in 32 & 64bits OS

You can compile your own kernel on i686 with the 'bigmem' option if I'm not mistaken and address >3 Gigs

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs

skottish

Forum Fellow

From: Here

Registered: 2006-06-16

Posts: 7,942

Re: Differences of RAM used with a config in 32 & 64bits OS

@skottish: Why, you just blew my mind. Mine is 36 physical/48 virtual. Thank you for the eye opener, I will definitely research this more now

My laptop has the same specs as you posted. The above was from my workstation.

flamelab

Member

From: Athens, Hellas (Greece)

Registered: 2007-12-26

Posts: 2,160

Re: Differences of RAM used with a config in 32 & 64bits OS

You can compile your own kernel on i686 with the 'bigmem' option if I'm not mistaken and address >3 Gigs

PAE is not a good workaround and should be used unless it's very necessary.

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: Differences of RAM used with a config in 32 & 64bits OS

@flamelab - why is that?

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CPU-optimized Linux-ck packages @ Repo-ck  • AUR packages • Zsh and other configs

flamelab

Member

From: Athens, Hellas (Greece)

Registered: 2007-12-26

Posts: 2,160

Re: Differences of RAM used with a config in 32 & 64bits OS

@flamelab - why is that?

See this at first

http://bbs.archlinux.org/viewtopic.php? … 48#p640348

I agree with Allan at all points, each time the "PAE" issue comes and goes within the forum regarding the stock i686 kernel26.

And that's because I've tested that myself, it's not worth the try, unless you can't do differently (highly critical, old, i686 machine)