Curiosity

[Any Uneven Jots]

Dear sirs,

I wondered if you could answer my question:

I have Windows XP Professional SP 3 2002 installed on my computer. I
have 2 GB of RAM and an AMD Phenom II X4 810 processor - 2.61 GHZ x 4
- quad core.

I believe there is a limit on the memory I can install on the 32-bit
edition - up to 4GB's? Is there also a processing power limit due to
my having 32 bit?

 

[Shenan Stanley]

I wondered if you could answer my question:

I have Windows XP Professional SP 3 2002 installed on my computer. I
have 2 GB of RAM and an AMD Phenom II X4 810 processor - 2.61 GHZ x
4 - quad core.

I believe there is a limit on the memory I can install on the 32-bit
edition - up to 4GB's? Is there also a processing power limit due to
my having 32 bit?

4GB - yes - although you won't ever see that much in 32-bit Windows.

Processing power limit - no.

 

[Ken Blake, MVP]

Dear sirs,

I wondered if you could answer my question:

I have Windows XP Professional SP 3 2002 installed on my computer. I
have 2 GB of RAM and an AMD Phenom II X4 810 processor - 2.61 GHZ x 4
- quad core.

I believe there is a limit on the memory I can install on the 32-bit
edition - up to 4GB's?

Yes, but that number is misleading.

All 32-bit client versions of Windows (not just Vista/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 is not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's 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 to.

Let me also mention that how much RAM you can make effective use of
depends on what programs you run. If you already have 2GB of RAM,
that's probably already more than you need, and adding any more would
do nothing for you.

Is there also a processing power limit due to
my having 32 bit?

No.

 

[Twayne]

Yes, but that number is misleading.

All 32-bit client versions of Windows (not just Vista/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 is not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's 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 to.

Let me also mention that how much RAM you can make effective use of
depends on what programs you run. If you already have 2GB of RAM,
that's probably already more than you need, and adding any more would
do nothing for you.




No.

I've always liked Tom Lee's explanation:

a.. A 32 bit OS can only use 4GB of memory total, that means if you
have 4GB of ram and your graphic card has 1GB of ram, you have a total
of 5GB of memory.

a.. Out of that 5GB of memory, you can only use 4GB total. 1GB the
graphic card will take up, so now the 32bit OS can only use 3GB.

a.. Enabling PAE, will limit to the OS to 2GB total. What PAE does is
dedicate 2GB to OS and the other 2GB to anything other then the OS.
Apparently some people don't understand how PAE works and think that
some how it can magically make a 32bit XP use more then 4GB, which is
impossible, so after noticing my explanation is not getting through, I
thought a visual from MS itself might help sink it in, you can see it
here:
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx
a.. Vista 32bit can see only 3.5GB of ram total. The new sp1 only
reports how much memory you have intalled, not how much memory you can
use.