Intel 2U server 4GB RAM showing only 3GB

David Kirchner dpk at dpk.net
Wed Sep 28 07:10:32 PDT 2005


On 9/28/05, Nelis Lamprecht <nlamprecht at gmail.com> wrote:
> Hi,
>
> I have a new dual Xeon Intel 2U server which I'm configuring with
> FreeBSD 5.4 and I can't get it to see more than 3GB RAM. If I try use
> the MAXMEM=(4096*1024) option it fails to boot up and just resets
> itself. Do I need to use the PAE option ? ..I wouldn't think so as
> this is meant for >4GB.

Yeah, you'll need to use PAE. Some BIOS apparently remap the top few
hundred megabytes (I've seen it use up to 768MB or so) for PCI (-X,
-Express?) devices.

FreeBSD 5.4-RELEASE, unpatched, has a bug that causes kernel panics
when you use PAE and memory above the 4GB barrier is accessed. The bug
is fixed in 5.4-STABLE, as of a while ago. I'm not sure if it made it
back in to any of the 5.4-RELEASE-p?? patches.


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