64-bit XP OS uses memory more efficiently than 32-bit?

[Spin]

Gurus,

Is it true that a 64-bit XP OS will get more out of a 4GB RAM system than a
32-bit XP OS will? In other words, the 64-bit version will use the RAM more
efficiently? I imagine the same efficiencies are true for Windows server?

 

[Jim]

Gurus,

Is it true that a 64-bit XP OS will get more out of a 4GB RAM system than
a 32-bit XP OS will? In other words, the 64-bit version will use the RAM
more efficiently? I imagine the same efficiencies are true for Windows
server?

It will use all of the 4GB because the memory mapped IO region is far
removed from the RAM.
Jim

 

[Colin Barnhorst]

I suggest you ask this question in the
microsoft.public.windows.64bit.general newsgroup. The folks there are very
up to date on 64bit questions.

One reference you might want to look at is:
http://www.microsoft.com/windowsxp/64bit/facts/top10.mspx
and the White Paper by Charlie Russel which is linked in the Related Links
box on the right. Charlie is one of the most prolific posters in
64bit.general, which is why I am suggesting that you drop in there.

 

[Holz]

Gurus,

Is it true that a 64-bit XP OS will get more out of a 4GB RAM system
than a 32-bit XP OS will? In other words, the 64-bit version will
use the RAM more efficiently? I imagine the same efficiencies are
true for Windows server?

If you as 10 people you will get different answers. Depends for what
type of application, environment, etc.

 

[Bob I]

No, nothing as simple as that. 32 bit only has 4 GB address space, 64
bit is going to allow the full 4 GB of memory to be used. "Efficiently"
is subject to interpretation.

 

[Ken Blake, MVP]

Is it true that a 64-bit XP OS will get more out of a 4GB RAM system than a
32-bit XP OS will? In other words, the 64-bit version will use the RAM more
efficiently? I imagine the same efficiencies are true for Windows server?

It has nothing to do with "efficiency."

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.

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.

64-bit versions of Windows do not have the same limitation, and can
use the entire 4GB.

However, note that unless you run very memory-hungry applications
(such as photographic editing or video-editing), even 3GB under
Windows XP is almost certainly *way* more RAM than you can make
effective use of. That means that from a practical standpoint, none of
what I said above will matter.