Re: 4GB RAM

[Lionel Elie Mamane <lionel@mamane.lu>]

On Tue, Feb 10, 2004 at 01:38:37PM +0100, Lionel Elie Mamane wrote:
> On Tue, Feb 10, 2004 at 09:16:25AM +0100, Andreas Wohlfeld wrote:
>> On Tue, Feb 10, 2004 at 09:03:30AM +0100, Lionel Elie Mamane wrote:

>>> NForce3 150 Pro chipset) with 4GB of memory installed: The BIOS (and
>>> thus Linux) recognises only between about 2.5GB and 3.5GB of RAM,

>> You have to read the mainboard manual.
>> It states that this is normal behavior due to memory space
>> allocation of chips on the mainboard and graphics card.

>> It's a limitation of the 32 bit architecture. It does not happen
>> with server mainboards in 40 bit flat or 36 bit PSE mode.

> Well, but then I would expect that a 64 bit Linux would go in 40 bit
> flat mode. Do I need to pass it a special boot parameter for this?

For the sake of the archives and people having the same problem:

1) Upgrade BIOS to Revision 1007.

   http://www.asus.com.tw/support/download/item.aspx?ModelName=SK8N

2) A new setting appears in the CMOS, "Northbridge config": "Remap
   above 4GB". This maps the "memory space allocation of chips on the
   mainboard and graphics card" above the 4GB barrier, thus permitting
   the OS to access the whole of the installed 4GB.

> Do the Opteron CPU's support PSE at all?

Yes, they do.

-- 
Lionel