Memory XP does not use

  • Thread starter Thread starter titus12
  • Start date Start date
T

titus12

I have 4GB of memory. I know XP 32bit will not see all of it. I've read
that the memory is maped someware else. If the mapping is true, how is the
memoy used?

Thank you,
David
 
you can likely get
more info at microsoft.com

search for pae
i.e., physical address extension
 
Andrew said:
XP 32bit uses up to 4GB.
Click to expand...

If your hardware supports it. Mine doesn't. The memory controller fitted
to my PC has a hardware limit of 3Gb, documented by the manufacturer.
This is common in Laptops and some desktops.
 
titus12 said:
I have 4GB of memory. I know XP 32bit will not see all of it. I've read
that the memory is maped someware else. If the mapping is true, how is the
memoy used?
Click to expand...

It isn't the memory that that is used somewhere else. It is the memory
*address* that is used elswewhere, specifically as the input output address
for other hardware such as sound cards, graphic cards, port interfaces, disc
controllers and so on and so on. Once the address is so used, it is
unavailble to access the memory itself. the amount so remapped varies from
installation to installation (depending on fitted hardware), but an
available memory size of 3.2 to 3.5 Gb is typical.
 
I have 4GB of memory. I know XP 32bit will not see all of it. I've read
that the memory is maped someware else. If the mapping is true, how is the
memoy used?
Click to expand...


All 32-bit versions of Windows (not just XP) have a 4GB address space.
That's the theoretical upper limit beyond which you can not go.

But you can't use the entire 4GB of address space. Even though you
have a 4GB address space, you can only use *around* 3.1GB of RAM.
That's because some of that space is used by hardware and not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but is
usually around 3.1GB.


Note that the hardware is using the address *space*, not the actual
RAM itself. The rest of the RAM goes unused because there is no
address space to map it too.
 
Back
Top