where's my memory?

[Shannon McMackin]

On 07/14/2009 12:01 PM, Joerg Bergmann wrote:
> Am 14.07.2009 16:39, schrieb Alan Cox:
>> On Tue, 14 Jul 2009 07:43:06 -0400
>> Neal Becker<ndbecker2 at gmail.com> wrote:
>>
>>> I have a argument with another user about memory. He claims that on
>>> running
>>> linux on his 4G Dell machine, top only reports 3.something memory, he
>>> says
>>> the missing space is for pci bus. I think this is only because he's
>>> running
>>> 32 bit and that 64 bit would give all the memory.
>>
>> Plenty of chipsets don't support mapping the RAM covered by the PCI
>> window up to the end of memory, especially older ones.
>>
>
> Just a remark: On my fedora 11 system (phenom II, 4GB RAM,
> 32 bit, PAE) top reports 3.9GB RAM. On my opinion, this is
> thanks to PAE.
>
> Joerg
>
On my F11 install running the PAE kernel, I get 4045988k as the total in 
top.  Some machines have difficulty using all available ram for many 
reasons.  I also noticed that an x86_64 kernel on the same machine gave 
me the 3.9gb as reported.