Fedora 10 memory usage

ghendric · 01-15-2009, 09:47 AM

Can Fedora 10 64 bit recognize more than 3 gigs of RAM?

Thanks

ronlau9 · 01-15-2009, 09:59 AM

Quote:

Originally Posted by ghendric

Can Fedora 10 64 bit recognize more than 3 gigs of RAM?

Thanks

Mine is 4 GB fully recognized by Fedora 10 X86_64

rjswilson · 01-15-2009, 10:13 AM

Yes it can. have 8GB of RAM on my server and it recognizes it

Cottsay · 01-15-2009, 10:34 AM

I wouldn't worry about reaching Fedora memory limit. Something tells me its up by 32 gigs or something absurd like that...

--scott

johnsfine · 01-15-2009, 12:25 PM

Quote:

Originally Posted by ghendric

Can Fedora 10 64 bit recognize more than 3 gigs of RAM?

Any distribution of 64-bit Linux can recognize over 4GB and many distributions of 32-bit Linux can recognize over 4GB.

But for support beyond about 3.25GB of RAM any of those require that the motherboard chipset supports address space beyond 4GB and that the BIOS properly initialize that chipset support.

If you have a problem with ram beyond about 3.25GB, then maybe you have a problem with the BIOS or chipset. Most releases of 32 bit Windows and some builds of 32-bit Linux hit that limit even if BIOS and chipset support more; But many builds of 32-bit Linux work beyond that limit, so a problem with one of those means the limit is in the BIOS or chipset.

If your BIOS or chipset (or OS) is limited to 4GB, that does not mean it supports a nearly full 4GB. If it doesn't support more than 4GB, it actually doesn't support more than about 3.25 GB (the exact limit depends on the BIOS and might be almost 3.7GB or barely over 3GB or anywhere in between).

farslayer · 01-15-2009, 02:30 PM

You are all thinking small..

Quote:

the real current upstream kernel hard memory limit on x86-64 is 44 bits, i.e. 16 TB.

http://linux.derkeiler.com/Mailing-L.../msg05965.html

Any lower limitation is a limitation of your hardware or BIOS.

ronlau9 · 01-16-2009, 03:42 AM

Quote:

Originally Posted by farslayer

You are all thinking small..

http://linux.derkeiler.com/Mailing-L.../msg05965.html

Any lower limitation is a limitation of your hardware or BIOS.

Well the user manual of youŕe Mobo will tell you what the limitations is.
And sometimes it is wise to upgrade the BIOS

farslayer · 01-16-2009, 02:18 PM

The question was, can the OS recognize more than 3GB.. not what is the limitation of a particular motherboard. and the answer is absolutely it can.

Although I agree the Motherboard limitation is definitely something you should check before purchasing more RAM.. One does need to take into account all factors when configuring a system.

johnsfine · 01-16-2009, 02:35 PM

Quote:

Originally Posted by farslayer

The question was, can the OS recognize more than 3GB.

Most of us try to guess what the OP should have asked and answer that. Otherwise, the second post in this thread could have been "Yes" and nothing further would be appropriate.

In this case, we (maybe mainly me) seem to have gone a bit overboard, given the lack of any follow up by the OP. But I will continue answering more than was asked, when it seems appropriate.

ghendric · 01-16-2009, 11:11 PM

I have the AsRock 939Dual-VSTA motherboard (http://www.asrock.com/mb/overview.as...ual-VSTA&s=939) and at boot up, it says that I have 3.2 gigs of RAM even though I really have 4 gigs installed. Vista 64 bit sees all 4 gigs just fine, but Fedora 10 reports only 3.1 in System Monitor.

ronlau9 · 01-16-2009, 11:51 PM

Quote:

Originally Posted by ghendric

I have the AsRock 939Dual-VSTA motherboard (http://www.asrock.com/mb/overview.as...ual-VSTA&s=939) and at boot up, it says that I have 3.2 gigs of RAM even though I really have 4 gigs installed. Vista 64 bit sees all 4 gigs just fine, but Fedora 10 reports only 3.1 in System Monitor.

What is output of the command free in fedora ?

Hitboxx · 01-17-2009, 01:39 AM

I also have a such type of mobo, and it does indeed say as 3.1 in my 64bit F10 and also Win XP 32bit. However this is a problem of the motherboard (DRM anyone). It is tied into for (Windows)Vista only.

Quote:

*Due to the chipset limitation, the actual memory size may be less than 4GB for the reservation for system usage under Windows® XP, Windows® XP 64-bit, Windows® Vista™ and Windows® Vista™ 64-bit.

This is from my motherboard's details http://www.asrock.com/mb/overview.as...7%20R2.0&s=775

800mb reserved for what stupid things I don't know. Also in the BIOS, I can see my 4gigs RAM as 2x2098 proper, but on booting during POST, it only shows 3200mb. So there you go.

Buying this product was a very stupid decision on my part although at the time my original Intel conked off and I was in dire need of a cheapo. I have learned my lesson and will never buy this company's products again.

johnsfine · 01-17-2009, 08:27 AM

Quote:

Originally Posted by ghendric

I have the AsRock 939Dual-VSTA motherboard (http://www.asrock.com/mb/overview.as...ual-VSTA&s=939) and at boot up, it says that I have 3.2 gigs of RAM even though I really have 4 gigs installed. Vista 64 bit sees all 4 gigs just fine, but Fedora 10 reports only 3.1 in System Monitor.

If Vista 64 can see all 4 gigs of RAM, then 64-bit Linux should also and some builds of 32-bit Linux should.

Try the command

Code:

dmesg | less

to look at log info from the startup of Linux (you may need to do it fairly soon after Linux startup to avoid having these log entries over written by later entries).

Look for a table similar to

Code:

BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009e800 (usable)
 BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000bbee0000 (usable)
 BIOS-e820: 00000000bbee0000 - 00000000bbee3000 (ACPI NVS)
 BIOS-e820: 00000000bbee3000 - 00000000bbef0000 (ACPI data)
 BIOS-e820: 00000000bbef0000 - 00000000bbf00000 (reserved)
 BIOS-e820: 00000000bc000000 - 00000000c0000000 (reserved)
 BIOS-e820: 00000000f0000000 - 00000000f2000000 (reserved)
 BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000000240000000 (usable)

That tells you the info the BIOS gave to Linux about the ram. If the amount of ram is not what you expect, that table tells you whether the problem is in the info passed from the BIOS to Linux or whether it is in Linux itself.

If you find that table, but don't understand the contents, paste it into a post in this thread and someone will explain it.

johnsfine · 01-17-2009, 08:34 AM

Quote:

Originally Posted by Hitboxx

I also have a such type of mobo, and it does indeed say as 3.1 in my 64bit F10 and also Win XP 32bit. However this is a problem of the motherboard (DRM anyone). It is tied into for (Windows)Vista only.

Notice the key difference in the phrasing of the footnote about the ram limit between the mobo documentation you linked to and the documentation the OP linked to.

In your copy it says "chipset limitation" meaning the limit applies to all OS's.

In the OP's copy it says "operating system limitation" meaning it applies only to some 32-bit OS's and not to 64-bit OS's.

Hitboxx · 01-17-2009, 11:44 PM

Yeah I saw that, was more of a let go rant