Addresses mapped
4GB of RAM installed
|---------------------|--------------|------|---|
1-2 GB for OS
2 GB for program "The hole"
| ~750MB |
Device
|------|--||
Video BIOS etc.

On your computer, you have a video card that has it's own memory. To make it
work faster, it is mapped as part of your RAM. You cannot have two areas of
memory with the same addresses, so the 750 MB of RAM above 3.12 GB is
"blocked", "re-routed" or "reserved" so that (in this case) the video card
can use those addresses for direct access to the processor. Other devices
_may_ do the same thing: Sound, BIOS, etc. So, the whole block of RAM is
"reserved." If you have a super-video card, you may even see less than 3GB.

When you only have 3GB installed, those addresses are not duplicated, so
they do not need to be "blocked" from program use and you see the whole 3GB.
When you have 4GB installed, those "reserved" addresses are blocked from
your use and available memory appears impaired.

The devices need unique addresses. 32-bit is limited to 4GB and the Vista
(32-bit) actually limits you to 3.12 GB because the "hole" must exist. So,
even with gimmicks, you can't get more because the devices need those
addresses. Instead, you can claim some of the OS operating space at a cost of
OS efficiency.
Gimmicks:
/PAE gives four more bits to the address bus (36-bits), but cannot be used
if you have less than 4GB of RAM installed:
http://msdn2.microsoft.com/en-us/library/aa366796.aspx
bcdedit /set increaseuserva (used to be /3GB) can be use to re-divide the
program/kernel memory usage:
http://msdn2.microsoft.com/en-us/library/bb613473.aspx
Use both with caution since they require certain setups to exist and impose
new limitations.

A 64-bit OS will allow you to use more memory, but the hole still exists (it
will vary in size) because those devices are _typically_ hard-coded to those
addresses.




" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

With a 64Bit OS the OS addresses can start at 750 and can go to 4750 so you
don't loose any actual space because of the reserve for hardware requiring
system addresses.


"Mark" wrote in message
...
Addresses mapped
4GB of RAM installed
|---------------------|--------------|------|---|
1-2 GB for OS
2 GB for program "The hole"
| ~750MB |
Device
|------|--||
Video BIOS etc.

On your computer, you have a video card that has it's own memory. To make
it
work faster, it is mapped as part of your RAM. You cannot have two areas
of
memory with the same addresses, so the 750 MB of RAM above 3.12 GB is
"blocked", "re-routed" or "reserved" so that (in this case) the video card
can use those addresses for direct access to the processor. Other devices
_may_ do the same thing: Sound, BIOS, etc. So, the whole block of RAM is
"reserved." If you have a super-video card, you may even see less than
3GB.

When you only have 3GB installed, those addresses are not duplicated, so
they do not need to be "blocked" from program use and you see the whole
3GB.
When you have 4GB installed, those "reserved" addresses are blocked from
your use and available memory appears impaired.

The devices need unique addresses. 32-bit is limited to 4GB and the Vista
(32-bit) actually limits you to 3.12 GB because the "hole" must exist. So,
even with gimmicks, you can't get more because the devices need those
addresses. Instead, you can claim some of the OS operating space at a cost
of
OS efficiency.
Gimmicks:
/PAE gives four more bits to the address bus (36-bits), but cannot be
used
if you have less than 4GB of RAM installed:
http://msdn2.microsoft.com/en-us/library/aa366796.aspx
bcdedit /set increaseuserva (used to be /3GB) can be use to re-divide the
program/kernel memory usage:
http://msdn2.microsoft.com/en-us/library/bb613473.aspx
Use both with caution since they require certain setups to exist and
impose
new limitations.

A 64-bit OS will allow you to use more memory, but the hole still exists
(it
will vary in size) because those devices are _typically_ hard-coded to
those
addresses.




" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

I'm showing 3.50 GB of RAM on a 4GB system.

" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

If you have not previously read the following KB article it may shed some
light on your problem.

http://support.microsoft.com/kb/929605/en-us


"GregM" wrote in message
...
I'm showing 3.50 GB of RAM on a 4GB system.

" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

I have read thread and referenced KB articles. But what is unclear is whether
I am getting any performance benefit from 4gig. That is, is the 750 mb
reserved for addresses enhancing my performance in any way? Or did I just pay
for an extra gig that does me no good?

"JW" wrote:

If you have not previously read the following KB article it may shed some
light on your problem.

http://support.microsoft.com/kb/929605/en-us


"GregM" wrote in message
...
I'm showing 3.50 GB of RAM on a 4GB system.

" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

You are getting marginal benefit from the extra gig,,, but leave
it in.

"GaryReger" wrote in message ...
I have read thread and referenced KB articles. But what is unclear is whether
I am getting any performance benefit from 4gig. That is, is the 750 mb
reserved for addresses enhancing my performance in any way? Or did I just pay
for an extra gig that does me no good?

"JW" wrote:

If you have not previously read the following KB article it may shed some
light on your problem.

http://support.microsoft.com/kb/929605/en-us


"GregM" wrote in message
...
I'm showing 3.50 GB of RAM on a 4GB system.

" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

In message
GaryReger wrote:

I have read thread and referenced KB articles. But what is unclear is whether
I am getting any performance benefit from 4gig. That is, is the 750 mb
reserved for addresses enhancing my performance in any way? Or did I just pay
for an extra gig that does me no good?

There is no benefit in that last 750MB -- However, you are getting
benefit from the remainder of that gig.

More importantly though, that probably means you have 4x1GB sticks,
which probably means dual channel mode is available. This gives some
extra performance, so even though you aren't able to address or use the
last 750MB, you're better off with that stick in then without it.

--
You can get more with a kind word and a 2x4 than just a kind word.

If your Vista 64 GB system is showing that all 4GB are supported then you
are getting a lot of benefit especially if you run applications that use a
lot of memory such as video file conversions. In any case if all 4GB are
supported then all of it that is not currently in use will be used for disk
caching which can greatly increase the response time of reading files off of
disk such as video or photo files which have not been recently used or time
shifted video if you are using MC with TV programming.

"GaryReger" wrote in message
...
I have read thread and referenced KB articles. But what is unclear is
whether
I am getting any performance benefit from 4gig. That is, is the 750 mb
reserved for addresses enhancing my performance in any way? Or did I just
pay
for an extra gig that does me no good?

"JW" wrote:

If you have not previously read the following KB article it may shed some
light on your problem.

http://support.microsoft.com/kb/929605/en-us


"GregM" wrote in message
...
I'm showing 3.50 GB of RAM on a 4GB system.

" wrote:

Hello,
Just read the longest post on this issue with no result so let try
again.
If i have 4 gig, only 3 shows, 750mb is reservered for the system.
Doesn't that seem a little stupid? If i have 3 gig of ram, 3 gig
shows in vista, here it has not needed to reserve 750mb. So why does
the first scenario need 750 for the system, and the second does not?
This would mean that the second does not have any ram for its system,
same devices and os. I would have thought that both situations would
result in having 750 stripped for the system. My old box, XP 256 mb
ram all that was avaliable and did not need dedicated system ram.
Does anyone have a straight answer for this? Yes i could run 64 bit
os, but at the moment i want to get 4 gig running in my 32 bit
environment.

I tried the following switches with no change.
1. Reboot Vista to safe mode with command line
2. Run the command : bcdedit /set PAE ForceEnable
3. Run bcdedit again to verify the switch is added
4. Reboot the system and check whether the problem is fixed

This is from the original post:

http://groups.google.com.au/group/mi...dbc2867738d289

"LOL, I was scratching my head over that one too. By definition, a 32-
bit CPU
can directly address up to 4GB of memory. But apparently nearly 1GB of
that
is reserved for devices. So the most you can possibly see is 3.12GB in
a
32-bit system. The way I read it, there is no way around it, no "fix"
if
you're using a 32-bit version of Vista.

To see any more than 3.12 GB you have to be using a 64-bit version of
Vista
plus meet all those other requirements (64-bit CPU instruction set,
chipset
with 8GB address space, BIOS that supports memory remapping). That's
the way
I read it anyway.

I think the DEP/ PAE thing is a whole different (but related) issue. "

In the article I read about turning on PAE in a 32 bit OS it said this:

"On a computer that supports hardware-enabled Data Execution Prevention
(DEP) and is running a 32-bit version of the Windows operating system that
supports DEP, PAE is automatically enabled when DEP is enabled and, on all
32-bit versions of the Windows operating system, except Windows Server 2003
with SP1, PAE is disabled when you disable DEP."


My Vista system automaticly turned on DEP when I installed it and it is
running now for "essential windows and programs and services only" does this
still mean that PAE is enabled and working now on my system?