How much Memory can Vista 32 bit support?

[Guest]

My machine has 4 GB of RAM. I need to know absolutely if Vista 32 Bit RTM
will support this? I know for a fact that Windows XP Professional 32 bit
only supports up to 3 GB. I am certain Vista 64 will. Please do not answer
this question unless you are certain.

Thank you

 

[Rick Rogers]

Hi,

I'm certain that you will not be able to use all 4GB with the x86 version.
This is a limitation of 32-bit processing. There is only 4GB of addressing
space and some of this is used by the system. How much depends on the
hardware, but it is the remainder that can be used by memory addressing. So,
the max you can address is 4GB minus however much your system requires. This
figure could be 3.2GB, or only 2.9GB, or some other figure entirely.

Yes, you are correct that the x64 version will allow you to use all 4GB.
There are a tremendously larger amount of addresses available under 64-bit
processing.

--
Best of Luck,

Rick Rogers, aka "Nutcase" - Microsoft MVP

Windows help - www.rickrogers.org

 

[Colin Barnhorst]

All 32bit operating systems can see a maximum of 4GB. It is a mathematical
limit, not the OS. Vista x86 like XP x86 will show a little over 3GB on
System Properties. This is normal. The "missing" ram is not really
missing. It is used by the system and not presented to the user. There is
a range of addresses at the upper end of 4GB that is reserved. In a system
with less than 4GB these are logical addresses and are handled by the system
that way. However, when the system has 4GB it must block out physical ram
to protect the reserved addresses. In addition, the BIOS will reserve some
additional address space for use by devices detected by the BIOS.

 

[Guest]

Colin, Rick, I thank you both for the response. Being a technet
subscriber, I have been agonizing (yes i read the other threads on this)
whether I should go with 64 bit or 32 bit. Colin, if I understand you, the 4
GB of RAM will be used as needed by Vista 32 bit, but just not seen by the
OS, is that correct?

Seasons Greetings to one and all who read this!

 

[Colin Barnhorst]

By the OS and the BIOS.

In a 64bit system the OS uses much higher logical address spaces so the OS
will see all 4GB of physical ram. Only when you had 128GB of physical ram
on a 64bit system would you see any physical ram reserved.

 

[Colin Barnhorst]

The "missing" ram is seen by the OS, just not by the user.

 

[Guest]

Colin, the problem I am facing is that I have an ultra ATA Adaptec card. It
is impossible to find 64 bit drivers. It may never be supported. I need
this card. It works fine with Vista 32 bit. However, I have 4 Gb of RAM.
My wife is arguing with me to upgrade to the 32 bit version of Vista, and
remove a RAM chip, as she believes that Vista 32 will not use it in any way.
So, my question, if I upgrade to vista 32 bit,
will the OS be able to use the extra RAM? Or will it just be a dummy chip
sitting there? I understand I won't see it except when the PC posts during
startup..

 

[Guest]

Thank You! It is being used, just not seen in the properties. I believe I
will go with the 32 bit version and keep the extra RAM! I am in Henderson
Nevada, where is everyone else at?

 

[Tom Lake]

Thank You! It is being used, just not seen in the properties. I believe I
will go with the 32 bit version and keep the extra RAM! I am in Henderson
Nevada, where is everyone else at?

Why not go with the 64-bit version and actually be able to USE all 4GB?

Tom Lake
Malone, NY

 

[Guest]

Whereas I do technical support VIA the phone for a living it is different
when it is your own hardware. I did find an article on MS that addresses
this issue specifically: for one and all:

http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx

 

[Guest]

Tom: Because it is almost impossible to find some 64 bit drivers for my
hardware.
As I study the problem further, I see that Windows 32 bit actually does use
up to 4 GB of RAM. The system apparently reserves 1 GB of RAM for use, such
as onboard graphics, etc.

 

[Colin Barnhorst]

The ram allocation will done on the same principles as XP.

It is not a dummy chip under Vista any more than it is under XP.

It relieves the OS from having to use logical address space translation but
because it is system address space the OS must fence it off to keep user
programs from colliding with the system. There is no difference between XP
and Vista in this regard except that Vista may fence off a little more than
XP needed.

Vista does indeed use the space. The user can't tell much difference
between 3GB and 4GB but the OS sure can.

 

[Colin Barnhorst]

He can't find a 64bit driver for a needed card.

Why not go with the 64-bit version and actually be able to USE all 4GB?

Tom Lake
Malone, NY

 

[Colin Barnhorst]

I believe that the PAE swich only applies to 32bit editions of Server.

 

[Guest]

From what I've learned, the XP boot.ini by default addresses 2 GB of RAM for
programs.

however, if you add a 3 GB parameter to Windows XP boot.ini, this will be
allocated as needed by the OS thus:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP
Professional" /noexecute=optin /fastdetect /3GB

I simply added the 3GB and restarted, with no noticeable difference. The
missing 1 GB belongs to Windows XP. I presume when I upgrade to Vista 32 bit
it will be similar.

 

[Guest]

A word of caution: You might have seen the occasional Windows Server
deployment in which there was a /3GB switch used in the server’s BOOT.INI
file. The /3GB switch changes the memory allocation so that Windows is only
allocated 1 GB of address space, and user mode processes are allocated 3 GB
of address space. Splitting the address space like this helps Windows to
better manage high demand applications such as Exchange Server. However,
Windows is configured to have a 2 GB address space for the operating system
for a reason. If you use the /3GB switch, you can severely impact Windows
ability to run multiple applications simultaneously. Furthermore, you should
never use the /3GB switch on Small Business Server or on a domain controller.

 

[Guest]

More wisdom: So what does this 4 GB limit mean for 32-bit machines running a
Windows operating system? Windows is designed to address a full 4 GB memory
space. Windows splits the 4 GB of available memory address space into two
separate 2 GB address spaces. One of the 2 GB address spaces is used by the
Windows operating system, and the other 2 GB address space is used for user
mode processes (applications).

 

[Mike C.]

It's not just Windows, it's all systems. This is not OS specific, this is a
result of the BIOS. The system cna only "address" up to 32-bits of ram. When
hardware communicates, you're really just sending data to it just like you
would store data in memory. This is why hardware in your system uses a
"memory range".

There is no way around it in 32-bit processing, no special switches, no file
replacements, no nothing. The maximum addressable space is 4GB--period. Your
SYSTEM (not OS) has to use a certain amount of that to be able to
communicate with devices.

A 64-bit OS does not run into this limitation.

 

[Tim Draper]

My machine has 4 GB of RAM. I need to know absolutely if Vista 32 Bit RTM
will support this? I know for a fact that Windows XP Professional 32 bit
only supports up to 3 GB. I am certain Vista 64 will. Please do not answer
this question unless you are certain.

Thank you

1st hand experience m8...... i have 4x 1gb sticks in my rig. ran 32bit
vista, and it was the same ram limitaion than XP 32bit does - around
2.8gb seeable/useable.

for me to see ALL 4gb (4096mb to be precise) i've had to goto vista 64bit.
not quite as simple as that tho..... different versions of vista have
max limitations

see http://support.teloep.org/vistaver.htm for more info. gives both
32bit and 64bit limitations.

so just ya know, 100% definate on above info. 1st hand experience.
tim

 

[Mike Hall - MS MVP Windows Shell/User]

It supports/addresses 4gb.. it may see and be able to actively use as much
as 3.25gb or as little as 2.85gb depending upon the motherboard design..