Is XP using all memory?

[Edwin Smith]

OK, I've been researching this for a couple of hours and I can't find a
definitive answer. I recently upgraded my Windows XP Pro SP2 from 2 GB to 4
GB of ram. However System Properties only shows 3.18 GB of Ram and Physical
Address Extension. I have an AMD Athlon 64 but I'm running 32 bit XP.

I understand that PAE enables all of the available ram, even the remapped
ram above 4GB, to be addressed but where is it used?

Is it being used? If it is why doesn't XP show it? I know about the memory
hole for I/O and Rom etc... but Virtual memory system took this into account
long ago.

Forgive me for asking a much asked question but there's something I'm just
not getting.

Edwin

 

[Brett I. Holcomb]

XP can see and use 4 gig. However, some of the 4 gig is used by the
system and by cards - video being one culprit.

 

[Sean Bolster]

32 bit can only address 3.2 G of RAM even with vista sp1 which will report
the 4gig it still can only address 3.2gigs.


Hello Edwin,

 

[KingKong]

NOT all video cards use system ram.
Just having 4Gig or ram will not make a video card use some of it.

 

[jorgen]

I understand that PAE enables all of the available ram, even the
remapped ram above 4GB, to be addressed but where is it used?

It is true that PAE was designed to address more than 4GB, but in XP/SP2
is has a different purpose: to give support for DEP. The address space
above 4G will be ignored, so ram remapped above will not be used

 

[Gerry]

Edwin

http://members.cox.net/slatteryt/RAM.html


--



Hope this helps.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[Bob I]

Actually the amount of RAM that is visible, is entirely dependent on the
hardware installed and the memory addresses needed to communicate with
that hardware. 3.2 is just a relatively common value, but by no means a
rule or limit.