is there any way to get XP to recognize 4 gigs of ram?

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dragonslayer45895

[H]ard|Gawd
Joined
Feb 13, 2007
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My dad and me just built a system...while not the newest...it works good. The problem im having is that he has 4 gigs of DDR400 G. Skill and XP says he only has 2:eek: . He has all of the windows updates and stuff also. If you know of a way or why please let me know.

Thanks, Harley
 
dragonslayer45895 said:
My dad and me just built a system...while not the newest...it works good. The problem im having is that he has 4 gigs of DDR400 G. Skill and XP says he only has 2:eek: . He has all of the windows updates and stuff also. If you know of a way or why please let me know.

Thanks, Harley
Click to expand...

You need to install a 64 bit o/s to see and utilize all 4 gigabytes of memory.

Install either Windows Vista x86-64 or Windows XP Professional X86-64.

(Assuming he has a processor capable of running 64-bit extensions)



The reason for this is that 32-bit operating systems have a 4GB addressable memory limitation, and your peripherals with their own onboard memory eat into that address space too.
 
Blue Falcon said:
The reason for this is that 32-bit operating systems have a 4GB addressable memory limitation, and your peripherals with their own onboard memory eat into that address space too.
Click to expand...

That's a slight oversimplification. 32-bit OSs are capable of addressing more than 4GB, but MS specifically chose to not support it in any of their consumer OSs. This has nothing to do with an attempt to force people into 64-bit OSs, rather, there's software and drivers that have serious problems with memory remapping. I don't know if it's still an issue, but nVidia drivers used to flat out crash with more than 4GB space in Win2k3.
 
masteraleph, the simplified answer was all that was needed for this question. Harley, as suggested you'll need to use a 64-bit Windows version to make all that 4Gb of RAM available. 32-bit XP (or Vista) just can't make every bit of it available.


First thing you need to do, though, is check see if your systems BIOS is actually reporting all of the 4Gb RAM. 'Losing' 2Gb of it seems excessive. You generally only 'lose' an amount which roughly equals the amount of video memory on your graphics card plus a bit. So reboot the system and watch the 'Memory check' which occurs before Windows begins to load. Is all 4Gb being reported there? If not, your motherboard itself must have a problem recognising all of your RAM, and you'll need to find out why.
 
masteraleph said:
That's a slight oversimplification. 32-bit OSs are capable of addressing more than 4GB, but MS specifically chose to not support it in any of their consumer OSs. This has nothing to do with an attempt to force people into 64-bit OSs, rather, there's software and drivers that have serious problems with memory remapping. I don't know if it's still an issue, but nVidia drivers used to flat out crash with more than 4GB space in Win2k3.
Click to expand...

Umm, this isn't a Microsoft problem, this is a 32-bit OS problem. I would like to see your evidence that says a 32-bit OS can utilize more than 4GB of memory. Even a 32-bit Linux OS will not have enough addressing space for 4GB. This is the inherent structure of a 32-bit OS. In all actuality, you won't see more than 3.5GB and then you take out the amount of memory from your video card.
 
Blue Falcon said:
You need to install a 64 bit o/s to see and utilize all 4 gigabytes of memory.

Install either Windows Vista x86-64 or Windows XP Professional X86-64.

(Assuming he has a processor capable of running 64-bit extensions)



The reason for this is that 32-bit operating systems have a 4GB addressable memory limitation, and your peripherals with their own onboard memory eat into that address space too.
Click to expand...


You mean X64. X86 is 32bit and X64 is 64bit so X86-64 is impossible:p
 
Thanks for all of your replys.

First thing you need to do, though, is check see if your systems BIOS is actually reporting all of the 4Gb RAM. 'Losing' 2Gb of it seems excessive. You generally only 'lose' an amount which roughly equals the amount of video memory on your graphics card plus a bit. So reboot the system and watch the 'Memory check' which occurs before Windows begins to load. Is all 4Gb being reported there? If not, your motherboard itself must have a problem recognising all of your RAM, and you'll need to find out why.
Click to expand...

Yes the bios does report 4 gigs,

Heres his setup

skt 939 Atholon X2 3800
Biostar TForce NF4 mobo
4 gigs g. skill
2X Nvidea 7800GTs in SLI
250gig WD Sata 3.0gbs
Acer 20in LCD
Optical sound into digital surround sound receiver

Another question is....since he would need to move to X64 to get the full uses of the ram and stuff.....

Would games like Starcraft work in 64 bit? its the game he plays the most anymore.

Thanks, Harley
 
StarCraft should run fine. Before you consider making any changes, research the driver availability to make sure you have the drivers you need.
 
Supposedly, using the PAE switch during startup should be able to help you see all of your 4GB of RAM. Even with the switch, 4GB will still be the upper limit in 32-bit XP. I haven't tried this, but you may want to check it out. Tamper with your boot.ini file at your own peril.
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx

Something like this (your boot info may be different):
Code: 
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /sos /PAE
 
Langford said:
Supposedly, using the PAE switch during startup should be able to help you see all of your 4GB of RAM. Even with the switch, 4GB will still be the upper limit in 32-bit XP. I haven't tried this, but you may want to check it out. Tamper with your boot.ini file at your own peril.
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx

Something like this (your boot info may be different):
Code: 
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /sos /PAE
Click to expand...

The PAE switch does absolutely nothing as of SP2. Don't bother screwing around with it.

See http://dansdata.com/askdan00015.htm for more information. In case you don't want to read the entire thing, the relevant information:

The /PAE boot.ini switch, on NT-descended Windows flavours, activates the Physical Address Extension mode that's existed in every PC CPU since the Pentium Pro. That mode cranks the address space up to 64 gigabytes (two to the power of 36), and the computer can then give a 4Gb addressing block within that space - or even more, with extra tricks - to each of several applications.

PAE's no good to the everyday 3Gb-problem-afflicted user, though, for two reasons.

First, it presents 64-bit addresses to drivers, and thus causes exactly the same compatibility problems as a proper 64-bit operating system, except worse, because now you need PAE-aware drivers for 32-bit Windows, instead of just plain 64-bit drivers for a 64-bit OS. From a normal user's point of view, PAE gives you the incompatibility of a 64-bit operating system when you're still running a 32-bit OS.

For this reason, Microsoft changed the behaviour of the /PAE option in all versions of WinXP as of Service Pack 2. They fixed the endless driver problems by, essentially, making /PAE in XP not do anything. All versions of WinXP except for the x64 Edition now have a hard 4Gb addressing limit, no matter what hardware you use them on and what configuration you choose.
Click to expand...

And if that isn't enough, see this post on PAE by Linus Torvalds, creator of the Linux kernel: http://www.realworldtech.com/forums/index.cfm?action=detail&id=78966&threadid=78766&roomid=2
 
protias said:
Umm, this isn't a Microsoft problem, this is a 32-bit OS problem. I would like to see your evidence that says a 32-bit OS can utilize more than 4GB of memory. Even a 32-bit Linux OS will not have enough addressing space for 4GB. This is the inherent structure of a 32-bit OS. In all actuality, you won't see more than 3.5GB and then you take out the amount of memory from your video card.
Click to expand...

Typically most "32 bit" OSes these days support 36 bit addressing as others have mentioned, although it is usually not enabled. This means while a single process will only have a 32 bit addressable memory space, the logical addresses will be mapped to a much wider range of physical addresses (assuming the memory is actually there).
 
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