Re: 4GB Physical. Less than 3GB in Linux.

From: Jasper Spaans
Date: Tue Apr 17 2007 - 14:27:02 EST


On 4/16/07, Jeff Chua <jeff.chua.linux@xxxxxxxxx> wrote:
On 4/16/07, Robert Hancock <hancockr@xxxxxxx> wrote:
> Jeff Chua wrote:
> > I've noticed that with 4GB physical ram, I'm only see 3098000 MB on
> > the Dell 745, and 3107056MB on the IBM X60s.
> >
> > I've tested with CONFIG_HIGHMEM4G=y, CONFIG_HIGHMEM64G=y,
> > CONFIG_X86_PAE=y, but nothing makes any difference.
>
> Chipset limitation. It uses up most of the MMIO region above 3GB
> preventing RAM from being mapped there, and doesn't support remapping
> the covered RAM to above 4GB. Nothing the kernel can do about it.

Well, I guess I learned the hard way. So it's better not to buy 4GB
... it turns out to be the same as buying one with just 3GB RAM.

Might be a setting in the bios... look for something like memory hole,
memory remapping, 4G DRAM, etc.

VrGr,
--
Jasper Spaans http://jsp.vs19.net/

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