Windows XP Physical Memory Limitations

[Guest MPH-101]

I have an HP system running Windows XP Media Center Edition 2002 (SP2) that I

recently upgraded the RAM on since many of my applications and simple

Internet activities where thrashing the harddrive to death (I only had 512MB

of RAM before the upgrade). I now have 4GB of DDR2 RAM and the HP system

software recognizes all 4GBs of physical memory, so the installation is OK.

However, Windows only recognizes 3.11 GB. My system has a 3.06 GHz Pentium 4

CPU, for what that's worth. Many years ago when I used to really get into

operating system design, and the like, I used to have to create workarounds

with the memory limitations of MS-DOS and early versions of Windows (e.g.,

the old 512k limit in DOS and, hence, Windows 3.1). I have now evolved into

mostly a user these days and do not understand the newer versions of Windows

like I did the older versions. Am I up against a memory limitation with XP?

If so, is there a workaround that will allow me to use all 4GBs of RAM? Or

will I have to upgrade to Vista (yuk!)? Thanks for whatever assistance

anyone can provide.............

[Guest Unknown]

Re: Windows XP Physical Memory Limitations

 

4 Gigs cannot be addressed because some of the address bits are used for

other purposes. It is the hardware

architecture that limits it. Your computer is working correctly.

 

"MPH-101" <MPH-101@discussions.microsoft.com> wrote in message

news:ED073CDD-AAE2-4C34-92D7-3A44F3BD43F3@microsoft.com...

>I have an HP system running Windows XP Media Center Edition 2002 (SP2) that

>I

> recently upgraded the RAM on since many of my applications and simple

> Internet activities where thrashing the harddrive to death (I only had

> 512MB

> of RAM before the upgrade). I now have 4GB of DDR2 RAM and the HP system

> software recognizes all 4GBs of physical memory, so the installation is

> OK.

> However, Windows only recognizes 3.11 GB. My system has a 3.06 GHz

> Pentium 4

> CPU, for what that's worth. Many years ago when I used to really get into

> operating system design, and the like, I used to have to create

> workarounds

> with the memory limitations of MS-DOS and early versions of Windows (e.g.,

> the old 512k limit in DOS and, hence, Windows 3.1). I have now evolved

> into

> mostly a user these days and do not understand the newer versions of

> Windows

> like I did the older versions. Am I up against a memory limitation with

> XP?

> If so, is there a workaround that will allow me to use all 4GBs of RAM?

> Or

> will I have to upgrade to Vista (yuk!)? Thanks for whatever assistance

> anyone can provide.............

[Guest Ken Blake, MVP]

Re: Windows XP Physical Memory Limitations

 

On Sat, 15 Mar 2008 12:19:36 -0500, "Unknown" <unknown@unknown.kom>

wrote:

> 4 Gigs cannot be addressed because some of the address bits are used for

> other purposes. It is the hardware

> architecture that limits it. Your computer is working correctly.

>

> "MPH-101" <MPH-101@discussions.microsoft.com> wrote in message

> news:ED073CDD-AAE2-4C34-92D7-3A44F3BD43F3@microsoft.com...

> >I have an HP system running Windows XP Media Center Edition 2002 (SP2) that

> >I

> > recently upgraded the RAM on since many of my applications and simple

> > Internet activities where thrashing the harddrive to death (I only had

> > 512MB

> > of RAM before the upgrade). I now have 4GB of DDR2 RAM and the HP system

> > software recognizes all 4GBs of physical memory, so the installation is

> > OK.

> > However, Windows only recognizes 3.11 GB. My system has a 3.06 GHz

> > Pentium 4

> > CPU, for what that's worth. Many years ago when I used to really get into

> > operating system design, and the like, I used to have to create

> > workarounds

> > with the memory limitations of MS-DOS and early versions of Windows (e.g.,

> > the old 512k limit in DOS and, hence, Windows 3.1). I have now evolved

> > into

> > mostly a user these days and do not understand the newer versions of

> > Windows

> > like I did the older versions. Am I up against a memory limitation with

> > XP?

> > If so, is there a workaround that will allow me to use all 4GBs of RAM?

> > Or

> > will I have to upgrade to Vista (yuk!)? Thanks for whatever assistance

> > anyone can provide.............

 

 

No, there is no workaround, and it would be exactly the same in Vista.

 

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.

 

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 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.

 

 

 

--

Ken Blake, Microsoft MVP - Windows Desktop Experience

Please Reply to the Newsgroup

[Guest Bob Knowlden]

Re: Windows XP Physical Memory Limitations

 

The limitation is in desktop 32 bit Windows operating systems. (It also

applies to 32 bit versions of Vista.) Google would show you more hits on

that than anyone would care to read.

 

A 64 bit OS (XP 64 or Vista 64) would fix that. I'm not a software

professional, so I don't know whether any of your applications would benefit

from a 64 bit OS, but I imagine that you have no 64 bit applications. (32

bit applications run fine for me under Vista 64.)

 

If you needed more than 4 GB of RAM, you'd have no choice: the 32 bit OSes

don't support more than 4.

 

Return address scrambled. Replace nkbob with bobkn.

 

"MPH-101" <MPH-101@discussions.microsoft.com> wrote in message

news:ED073CDD-AAE2-4C34-92D7-3A44F3BD43F3@microsoft.com...

>I have an HP system running Windows XP Media Center Edition 2002 (SP2) that

>I

> recently upgraded the RAM on since many of my applications and simple

> Internet activities where thrashing the harddrive to death (I only had

> 512MB

> of RAM before the upgrade). I now have 4GB of DDR2 RAM and the HP system

> software recognizes all 4GBs of physical memory, so the installation is

> OK.

> However, Windows only recognizes 3.11 GB. My system has a 3.06 GHz

> Pentium 4

> CPU, for what that's worth. Many years ago when I used to really get into

> operating system design, and the like, I used to have to create

> workarounds

> with the memory limitations of MS-DOS and early versions of Windows (e.g.,

> the old 512k limit in DOS and, hence, Windows 3.1). I have now evolved

> into

> mostly a user these days and do not understand the newer versions of

> Windows

> like I did the older versions. Am I up against a memory limitation with

> XP?

> If so, is there a workaround that will allow me to use all 4GBs of RAM?

> Or

> will I have to upgrade to Vista (yuk!)? Thanks for whatever assistance

> anyone can provide.............

[Guest PD43]

Re: Windows XP Physical Memory Limitations

 

"Unknown" <unknown@unknown.kom> wrote:

>4 Gigs cannot be addressed because some of the address bits are used for

>other purposes. It is the hardware

>architecture that limits it. Your computer is working correctly.

 

However, his paragraphing isn't.

[Guest db ´¯`·.. >]

Re: Windows XP Physical Memory Limitations

 

perhaps the /pae

switch might provide

be of benefit:

 

http://msdn2.microsoft.com/en-us/library/aa366718.aspx

 

--

 

db·´¯`·...¸><)))º>

 

"MPH-101" <MPH-101@discussions.microsoft.com> wrote in message

news:ED073CDD-AAE2-4C34-92D7-3A44F3BD43F3@microsoft.com...

>I have an HP system running Windows XP Media Center Edition 2002 (SP2) that I

> recently upgraded the RAM on since many of my applications and simple

> Internet activities where thrashing the harddrive to death (I only had 512MB

> of RAM before the upgrade). I now have 4GB of DDR2 RAM and the HP system

> software recognizes all 4GBs of physical memory, so the installation is OK.

> However, Windows only recognizes 3.11 GB. My system has a 3.06 GHz Pentium 4

> CPU, for what that's worth. Many years ago when I used to really get into

> operating system design, and the like, I used to have to create workarounds

> with the memory limitations of MS-DOS and early versions of Windows (e.g.,

> the old 512k limit in DOS and, hence, Windows 3.1). I have now evolved into

> mostly a user these days and do not understand the newer versions of Windows

> like I did the older versions. Am I up against a memory limitation with XP?

> If so, is there a workaround that will allow me to use all 4GBs of RAM? Or

> will I have to upgrade to Vista (yuk!)? Thanks for whatever assistance

> anyone can provide.............

[Guest HeyBub]

Re: Windows XP Physical Memory Limitations

 

MPH-101 wrote:

> I have an HP system running Windows XP Media Center Edition 2002

> (SP2) that I recently upgraded the RAM on since many of my

> applications and simple Internet activities where thrashing the

> harddrive to death (I only had 512MB of RAM before the upgrade). I

> now have 4GB of DDR2 RAM and the HP system software recognizes all

> 4GBs of physical memory, so the installation is OK. However, Windows

> only recognizes 3.11 GB. ... Am I up against a memory limitation with

> XP? If so, is

> there a workaround that will allow me to use all 4GBs of RAM? Or

> will I have to upgrade to Vista (yuk!)? Thanks for whatever

> assistance anyone can provide.............

 

You are using the 32-bit version of XP.

 

2^32 = 4,294,967,296 is the most number of bytes XP can access. Subtract

those mandated for use by various hardware pieces and you're left with the

3.11GB shown (after making allowances for 1 GB = 1024 MB, 1 MB = 1024 KB and

other nerdish shorthand).

 

Upgrading to Vista-32 won't help. You can upgrade to XP-64 or Vista-64.

 

But all this begs the question: Did your hard drive quit thrashing?

 

If not, the cause of the thrash is something else and you just wasted your

money.

 

If your hard-drive DID quit thrashing, then your question here is more of a

curiosity item.

[Guest Colin Barnhorst]

Re: Windows XP Physical Memory Limitations

 

What are you doing that you feel you need additional ram for? If you have a

program that requires more ram than is supported by XP x86 then migrate to a

64bit computer and operating system. The 3GB that you are reporting is

simply the portion of the 4GB total that is available for user programs.

The system is allocated the remainder as described by others already. That

is the trade off for the high end video cards and other devices in use

today. Essentially, there are two of you using the computer; you and the

computer.

 

"MPH-101" <MPH-101@discussions.microsoft.com> wrote in message

news:ED073CDD-AAE2-4C34-92D7-3A44F3BD43F3@microsoft.com...

>I have an HP system running Windows XP Media Center Edition 2002 (SP2) that

>I

> recently upgraded the RAM on since many of my applications and simple

> Internet activities where thrashing the harddrive to death (I only had

> 512MB

> of RAM before the upgrade). I now have 4GB of DDR2 RAM and the HP system

> software recognizes all 4GBs of physical memory, so the installation is

> OK.

> However, Windows only recognizes 3.11 GB. My system has a 3.06 GHz

> Pentium 4

> CPU, for what that's worth. Many years ago when I used to really get into

> operating system design, and the like, I used to have to create

> workarounds

> with the memory limitations of MS-DOS and early versions of Windows (e.g.,

> the old 512k limit in DOS and, hence, Windows 3.1). I have now evolved

> into

> mostly a user these days and do not understand the newer versions of

> Windows

> like I did the older versions. Am I up against a memory limitation with

> XP?

> If so, is there a workaround that will allow me to use all 4GBs of RAM?

> Or

> will I have to upgrade to Vista (yuk!)? Thanks for whatever assistance

> anyone can provide.............