Mailing List Archive: Gentoo: User

[OT] Acer Core2Duo only sees 3G of RAM

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michaelkintzios at gmail

Dec 3, 2009, 2:14 PM

Post #1 of 9 (246 views)
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[OT] Acer Core2Duo only sees 3G of RAM

Hi All,

I booted up an Acer Core2Duo (P7550) with 4G of RAM using a Knoppix DVD and
only 3G of RAM is visible. Why would that be so? Both cores of the CPU are
recognised, so I think that the kernel is SMP enable. I attach the lspci
output in case you see something that explains it. Unfortunately, hwinfo
fails with an io segmentation ...
--
Regards,
Mick

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lspci.txt.zip (2.94 KB)

signature.asc (0.19 KB)

michaelkintzios at gmail

Dec 3, 2009, 2:44 PM

Post #2 of 9 (227 views)
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Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

Please ignore previous message ... I should have gone to bed by now because
evidently I am too tired to think clearly! O_O

I will try to boot up with a 64bit OS next.

On Thursday 03 December 2009 22:14:36 Mick wrote:
> Hi All,
>
> I booted up an Acer Core2Duo (P7550) with 4G of RAM using a Knoppix DVD and
> only 3G of RAM is visible. Why would that be so? Both cores of the CPU
> are recognised, so I think that the kernel is SMP enable. I attach the
> lspci output in case you see something that explains it. Unfortunately,
> hwinfo fails with an io segmentation ...
>

--
Regards,
Mick

Attachments:

signature.asc (0.19 KB)

alan.mckinnon at gmail

Dec 3, 2009, 2:45 PM

Post #3 of 9 (225 views)
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Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

On Friday 04 December 2009 00:14:36 Mick wrote:
> Hi All,
>
> I booted up an Acer Core2Duo (P7550) with 4G of RAM using a Knoppix DVD and
> only 3G of RAM is visible. Why would that be so? Both cores of the CPU
> are recognised, so I think that the kernel is SMP enable. I attach the
> lspci output in case you see something that explains it. Unfortunately,
> hwinfo fails with an io segmentation ...
>

I bet you used a 32 bit Knoppix

--
alan dot mckinnon at gmail dot com

michaelkintzios at gmail

Dec 3, 2009, 10:21 PM

Post #4 of 9 (228 views)
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Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

On Thursday 03 December 2009 22:45:29 Alan McKinnon wrote:
> On Friday 04 December 2009 00:14:36 Mick wrote:
> > Hi All,
> >
> > I booted up an Acer Core2Duo (P7550) with 4G of RAM using a Knoppix DVD
> > and only 3G of RAM is visible. Why would that be so? Both cores of the
> > CPU are recognised, so I think that the kernel is SMP enable. I attach
> > the lspci output in case you see something that explains it.
> > Unfortunately, hwinfo fails with an io segmentation ...
>
> I bet you used a 32 bit Knoppix

Yep! It's surprising how after a good night's sleep the most complex problems
suddenly solve themselves ... ha, ha! :-))
--
Regards,
Mick

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xav at gentooist

Dec 3, 2009, 11:51 PM

Post #5 of 9 (227 views)
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Re: Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

Hi,

You don't need to go to bed :) Just setup your kernel to use High-Memory:
cd /usr/src/linux; make menuconfig; then item:
Processor type and features -> High Memory Support -> 4GB
And it's done, but keep in mind that userspace processes will still be limited
to 3GB of memory use (AFAIK) (if someone would like to correct me, he is welcome).

If you want your processes to use more than 3GB of memory, then yes, boot up
with a 64bit OS (again correct me if i'm wrong) ;)

HTH.

Mick a �crit :
> Please ignore previous message ... I should have gone to bed by now because
> evidently I am too tired to think clearly! O_O
>
> I will try to boot up with a 64bit OS next.
>
> On Thursday 03 December 2009 22:14:36 Mick wrote:
>> Hi All,
>>
>> I booted up an Acer Core2Duo (P7550) with 4G of RAM using a Knoppix DVD and
>> only 3G of RAM is visible. Why would that be so? Both cores of the CPU
>> are recognised, so I think that the kernel is SMP enable. I attach the
>> lspci output in case you see something that explains it. Unfortunately,
>> hwinfo fails with an io segmentation ...
>>
>

--
Xavier Parizet
YaGB : http://gentooist.com
GPG : C7DC B10E FC21 63BE
B453 D239 F6E6 DF65 1569 91BF

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graham at gmurray

Dec 4, 2009, 4:21 AM

Post #6 of 9 (227 views)
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Re: Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

Xavier Parizet <xav [at] gentooist> writes:

> If you want your processes to use more than 3GB of memory, then yes, boot up
> with a 64bit OS (again correct me if i'm wrong) ;)

Or configure your 32bit kernel with HIGHMEM = 64GB

drew.kay at gmail

Dec 5, 2009, 10:00 PM

Post #7 of 9 (222 views)
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Re: Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

Isn't the memory hole above 3GB present even in the 64bit systems?
Something about the MMIO reservations for the PCI bus taking up the
top gig of the first four Gigs?

--
Drew

"Nothing in life is to be feared. It is only to be understood."
--Marie Curie

graham at gmurray

Dec 6, 2009, 1:18 AM

Post #8 of 9 (220 views)
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Re: Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

Drew <drew.kay [at] gmail> writes:

> Isn't the memory hole above 3GB present even in the 64bit systems?
> Something about the MMIO reservations for the PCI bus taking up the
> top gig of the first four Gigs?

I do not know. What I do know is that the system I am using here at home
has 6GB RAM, the one I use at work has 8GB, and I have seen a system
with 12GB all running Gentoo x86 (32 bit) and all of which report the
full amount of RAM as available.

neil at digimed

Dec 7, 2009, 3:06 AM

Post #9 of 9 (220 views)
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Re: Re: [OT] Acer Core2Duo only sees 3G of RAM [In reply to]

On Sat, 5 Dec 2009 22:00:00 -0800, Drew wrote:

> Isn't the memory hole above 3GB present even in the 64bit systems?
> Something about the MMIO reservations for the PCI bus taking up the
> top gig of the first four Gigs?

That's the case with some hardware, like my Asus motherboard. It was
fixed by changing a BIOS setting.

--
Neil Bothwick

Two is not equal to three, even for large values of two.

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