What is the max addressable memory for XP Home?

klk wrote:
> What is the max addressable memory for XP Home?

Posted multiple times.
(Although this time, you put something in themessage body. hah)

I'll repeat my answer, in case you also have trouble finding your previous
posts...

Now is a great time to point you to one of the easiest ways to find
information on problems you may be having and solutions others have found:

Search using Google!
http://www.google.com/
(How-to: http://www.google.com/intl/en/help/basics.html )

(You might consider putting *something* in the message body next time.
Even, "Thanks in advance" would have been better than blank. hah)

http://www.google.com/search?q=What+...+for+XP +Home
.... might lead you to ...
http://experi3nc3.wordpress.com/2007...32bit-utilise/
or
http://www.computing.net/answers/win...me/166667.html
or
http://www.crucial.com/kb/answer.aspx?qid=4251
(Among others. The latter is pretty definitive - as they wouldn't want you
returning your purchased memory.)

Answer:
4GB is the max supported, 'accessible to your programs' will range between
2.5 and 3.75GB - with anything above 3.25GB being doubtful.

Although - most people who have Windows XP Home will likely never even
utilize a full 1GB - even with a shared memory video card. ;-)

See the replies to your previous post.

"klk" <klk> wrote in message
news:98e4
: What is the max addressable memory for XP Home?

Thank you ... I guess you can tell this is my first time ... so many of the
post were so far over my head, I got frustrated. My system is a bunch of
hand-me-downs that I am trying to upgrade and my geek brother is making me
figure it out on my own. Thanks again! I'll get better.

"Shenan Stanley" wrote:
[..]

klk wrote:
> What is the max addressable memory for XP Home?

You can see an example here, of a system which has 4GB of
physical RAM installed, and a PCI video card. The BIOS
reserves some address space, for busses and I/O. That
leaves less address space, to get at the memory. Part
of the memory is then inaccessible. In the example
here, the machine reports "3.50 GB of RAM".

http://www.digitmemo.com/articles/10...olutionpart-1/

There is a difference between "memory" and "address space".
Hardware must have unique addresses, in order to be
accessed by the processor. Every attempt by the processor,
to visit hardware, starts with the presentation of an
address. The address is decoded, and a certain piece of
hardware is enabled in response. In the above example,
any accesses below an address like 3.5GB, causes the
memory controller to respond. Any address above 3.5GB,
results in one of the system busses being enabled, and
perhaps something like that PCI video card responds.

The memory itself is still 4GB in size. But the memory
controller has been configured, such that only the
lower 3.5GB is accessible.

------
^ <--- "can't touch that..."
----- |
^ |
| |
3.5GB 4GB
mapped memory
| |
v v
----- ------

When addresses above 3.5GB are used, a system bus
responds instead. The BIOS makes the allocations
during POST, and sets the TOM (top of memory)
register, so that the OS will understand what
resources have been reserved. If a PCI Express video
card was installed in the system, and it had a 1GB
video memory soldered onboard, then the map might
be modified to look like this.

------
^ <--- "can't touch that..."
|
----- |
^ |
| |
2.75GB 4GB
mapped memory
| |
v v
----- ------

Best case, installing 4GB, you might see 3.5GB listed,
if using a PCI video card. With high end video cards, and
a pair of them, there will be a significant modification
to the address space setup.

To answer your original question, the stated limits are
listed here. AFAIK, Home and Pro are the same.

http://msdn.microsoft.com/en-us/library/aa366778.aspx

"Physical Memory Limits: Windows XP

The following table specifies the limits on physical
memory for Windows XP.

Version Limit in 32-bit Windows Limit in 64-bit Windows

Windows XP 4GB 128GB
Windows XP 512 MB Not applicable
Starter Edition "

HTH,
Paul

"klk" <klk> wrote in message
news:762f

> Thank you ... I guess you can tell this is my first time ... so many of
the
> post were so far over my head, I got frustrated. My system is a bunch of
> hand-me-downs that I am trying to upgrade and my geek brother is making me
> figure it out on my own.

Post problems in the one newsgroup where you
are confident of good advice (or two, for hardware
and software) and follow up in timely fashion.

If you use Outlook Express for email and newsgroups
(recommended) you can flag any thread (in scarlet)
for convenience in following up. In the window that
lists subject lines, right click on the rightmost end of
the column headings, and from the menu you can
add WATCH/IGNORE to the display (and place it
where you find convenient.) When you click in this
column, the subject aline alongside is flagged for easy
viewing (and the newsgroup name also shown inn scarle:
the list thus reminds you to check your posts for replies.)