«

Dear All:

I just read the the "What are the General Memory Limits of Windows 64-bit?"
in
http://msdn.microsoft.com/isv/techno...q/default.aspx

The answer in the page is
"Virtual Address Space per 64 bit processes: 2 GB (4 GB with large
address aware) "


Is it correct?

I also had read the 64bit SDK document in
http://msdn.microsoft.com/library/de...ress_space.asp

It mentioned that
"By default, 64-bit Microsoft Windows-based applications have a
user-mode address space of 8 terabytes".

What is the fact? 8 terabytes or 4 GB?

If a 64bit application just uses max 4GB, I think it is not so interesting.



--
Jacky Kwok
jacky@alumni_DOT_cuhk_DOT_edu_DOT_hk
jacky@compose_DOT_com_DOT_hk

You know it is higher than 4GB. There are AMD Opteron motherboards out now
that support 128GB of RAM, so it has to be higher.



Wayne

Hello,
That page looks to be wrong, let me check on this.
Thanks,
Darrell Gorter[MSFT]

This posting is provided "AS IS" with no warranties, and confers no rights
--------------------
<Date: Tue, 21 Jun 2005 10:23:49 +0800
<From: Jacky Kwok <>
<User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317)
<X-Accept-Language: en-us, en
<MIME-Version: 1.0
<Subject: 64bit app - 8 terabytes or 4 GB?
<Content-Type: text/plain; charset=ISO-8859-1; format=flowed
<Content-Transfer-Encoding: 7bit
<Message-ID: <>
<Newsgroups: microsoft.public.windows.64bit.general
<NNTP-Posting-Host: 210.176.55.168
<Lines: 1
<Path: TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFT NGP15.phx.gbl
<Xref: TK2MSFTNGXA01.phx.gbl microsoft.public.windows.64bit.general:8131
<X-Tomcat-NG: microsoft.public.windows.64bit.general
<
<Dear All:
<
<I just read the the "What are the General Memory Limits of Windows 64-bit?"
<in
<http://msdn.microsoft.com/isv/techno...generalfaq/def
ault.aspx
<
<The answer in the page is
<"Virtual Address Space per 64 bit processes: 2 GB (4 GB with large
<address aware) "
<
<
<Is it correct?
<
<I also had read the 64bit SDK document in
<http://msdn.microsoft.com/library/de...-us/win64/win6
4/virtual_address_space.asp
<
<It mentioned that
<"By default, 64-bit Microsoft Windows-based applications have a
<user-mode address space of 8 terabytes".
<
<What is the fact? 8 terabytes or 4 GB?
<
<If a 64bit application just uses max 4GB, I think it is not so interesting.
<
<
<
<--
<Jacky Kwok
<jacky@alumni_DOT_cuhk_DOT_edu_DOT_hk
<jacky@compose_DOT_com_DOT_hk
<

That FAQ is wrong. Pure and Simple

--
Charlie.
http://www.msmvps.com/xperts64/


Jacky Kwok wrote:
> Dear All:
>
> I just read the the "What are the General Memory Limits of Windows
> 64-bit?" in
> http://msdn.microsoft.com/isv/techno...q/default.aspx
>
> The answer in the page is
> "Virtual Address Space per 64 bit processes: 2 GB (4 GB with large
> address aware) "
>
>
> Is it correct?
>
> I also had read the 64bit SDK document in
> http://msdn.microsoft.com/library/de...ress_space.asp
>
> It mentioned that
> "By default, 64-bit Microsoft Windows-based applications have a
> user-mode address space of 8 terabytes".
>
> What is the fact? 8 terabytes or 4 GB?
>
> If a 64bit application just uses max 4GB, I think it is not so
> interesting.

See, you're much politer than I. I said it's just plain wrong.

--
Charlie.
http://www.msmvps.com/xperts64/


"Darrell Gorter[MSFT]" wrote:
> Hello,
> That page looks to be wrong, let me check on this.
> Thanks,
> Darrell Gorter[MSFT]
>
> This posting is provided "AS IS" with no warranties, and confers no
> rights --------------------
> <Date: Tue, 21 Jun 2005 10:23:49 +0800
> <From: Jacky Kwok <>
> <User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317)
> <X-Accept-Language: en-us, en
> <MIME-Version: 1.0
> <Subject: 64bit app - 8 terabytes or 4 GB?
> <Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> <Content-Transfer-Encoding: 7bit
> <Message-ID: <>
> <Newsgroups: microsoft.public.windows.64bit.general
> <NNTP-Posting-Host: 210.176.55.168
> <Lines: 1
> <Path: TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFT NGP15.phx.gbl
> <Xref: TK2MSFTNGXA01.phx.gbl
> microsoft.public.windows.64bit.general:8131 <X-Tomcat-NG:
> microsoft.public.windows.64bit.general <
> <Dear All:
> <
> <I just read the the "What are the General Memory Limits of Windows
> 64-bit?" <in
> <http://msdn.microsoft.com/isv/techno...generalfaq/def
> ault.aspx
> <
> <The answer in the page is
> <"Virtual Address Space per 64 bit processes: 2 GB (4 GB with large
> <address aware) "
> <
> <
> <Is it correct?
> <
> <I also had read the 64bit SDK document in
> <http://msdn.microsoft.com/library/de...-us/win64/win6
> 4/virtual_address_space.asp
> <
> <It mentioned that
> <"By default, 64-bit Microsoft Windows-based applications have a
> <user-mode address space of 8 terabytes".
> <
> <What is the fact? 8 terabytes or 4 GB?
> <
> <If a 64bit application just uses max 4GB, I think it is not so
> interesting. <
> <
> <
> <--
> <Jacky Kwok
> <jacky@alumni_DOT_cuhk_DOT_edu_DOT_hk
> <jacky@compose_DOT_com_DOT_hk
> <

Actually, Wayne, "virtual memory address space" and RAM are two VERY
different things. It would be technically possible to support that much RAM
and still only have a 4GB Virtual Memory address space. Stupid, silly, and
not very efficient. But technically possible.

--
Charlie.
http://www.msmvps.com/xperts64/


Wayne Wastier wrote:
> You know it is higher than 4GB. There are AMD Opteron motherboards
> out now that support 128GB of RAM, so it has to be higher.
>
>
>
> Wayne

Those sound like the limits for 32bit apps to me, 2Gb or 4Gb when compiled
large memory aware. It definately isn't the limit for 64bit apps.

Peter Lawton

"Jacky Kwok" <> wrote in message
news:...
> Dear All:
>
> I just read the the "What are the General Memory Limits of Windows
> 64-bit?"
> in
> http://msdn.microsoft.com/isv/techno...q/default.aspx
>
> The answer in the page is
> "Virtual Address Space per 64 bit processes: 2 GB (4 GB with large address
> aware) "
>
>
> Is it correct?
>
> I also had read the 64bit SDK document in
> http://msdn.microsoft.com/library/de...ress_space.asp
>
> It mentioned that
> "By default, 64-bit Microsoft Windows-based applications have a user-mode
> address space of 8 terabytes".
>
> What is the fact? 8 terabytes or 4 GB?
>
> If a 64bit application just uses max 4GB, I think it is not so
> interesting.
>
>
>
> --
> Jacky Kwok
> jacky@alumni_DOT_cuhk_DOT_edu_DOT_hk
> jacky@compose_DOT_com_DOT_hk

To expand:

a.. What are the General Memory Limits of Windows 64-bit?

The memory limits for 64-bit Windows are:

a.. Total Virtual Address Space: 4 GB (32-bit) and 16 TB (64-bit) <--
Correct
b.. Virtual Address Space per 32-bit processes: 2 GB (3 GB with 3gb flag)
<-- Wrong.
c.. Virtual Address Space per 64 bit processes: 2 GB (4 GB with large
address aware) <-- WAY wrong
The correct answer is 4 GB for 32 bit processes compiled with the
/LARGEMEMORYAWARE switch, when running in x64's WOW64. No command line
switches are required. And for 64 bit processes, it's 8TB of address space.

--
Charlie.
http://www.msmvps.com/xperts64/


Jacky Kwok wrote:
> Dear All:
>
> I just read the the "What are the General Memory Limits of Windows
> 64-bit?" in
> http://msdn.microsoft.com/isv/techno...q/default.aspx
>
> The answer in the page is
> "Virtual Address Space per 64 bit processes: 2 GB (4 GB with large
> address aware) "
>
>
> Is it correct?
>
> I also had read the 64bit SDK document in
> http://msdn.microsoft.com/library/de...ress_space.asp
>
> It mentioned that
> "By default, 64-bit Microsoft Windows-based applications have a
> user-mode address space of 8 terabytes".
>
> What is the fact? 8 terabytes or 4 GB?
>
> If a 64bit application just uses max 4GB, I think it is not so
> interesting.

Charlie Russel - MVP wrote:
> Actually, Wayne, "virtual memory address space" and RAM are two VERY
> different things. It would be technically possible to support that
> much RAM and still only have a 4GB Virtual Memory address space.
> Stupid, silly, and not very efficient. But technically possible.

And it *has* been done: just think of the old times(TM) with EMS, HMS,
memory bank switching etc.

Kind regards

robert

Charles,

"Ahead of Computex 2005 in Taipei, AMDboard.com has another scoop regarding
the latest 8-way AMD Opteron motherboard from IWILL. Dual-core ready, the
IWILL H8502 is powered by the powerful NVIDIA NFORCE PRO 2200 & 2050 that
can provide up to 40 lanes PCI-Express bandwidth. The IWILL H8502 8-way AMD
Opteron server architecture also uses a special HTX technology to connect
the I/O controller to the system controller and can accommodate up to 128GB
of memory. All this allows an unprecedented level of performance required
for complex, highly technical computing and high performance parallel
applications as proven by Linpack benchmark raised 80% from 4-way to 8-way
system! "