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View Full Version : How much RAM can XP actually use?


sillyeagle
03-02-07, 11:57 PM
Somebody said 2GB is the most it will use. Is that accurate?

Xion X2
03-03-07, 12:01 AM
Do you mean how much it can actually use or how much can it recognize? I believe that it can recognize up to about 2.8GB. At least in 32-bit mode.

SLippe
03-03-07, 12:07 AM
I was thinkin' it was like 3.3 or somewhere around there. I know it's not the full 4GB.

Rytr
03-03-07, 12:10 AM
3.3 is what I got when I tried 4GB.

sillyeagle
03-03-07, 12:11 AM
Yeah how much is will recognize/take advantage of.

I just found this, which says it only uses 2GB. Anybody know the difference between the 2GB referenced here and the 3.3GB thats shows in windows?

Windows XP Professional and Windows Server 2003 Memory Support. The maximum amount of memory that can be supported on Windows XP Professional and Windows Server 2003 is also 4 GB. However, Windows Server 2003, Enterprise Edition supports 32 GB of physical RAM and Windows Server 2003, Datacenter Edition supports 64 GB of physical RAM using the PAE feature.

The virtual address space of processes and applications is still limited to 2 GB unless the /3GB switch is used in the Boot.ini file. When the physical RAM in the system exceeds 16 GB and the /3GB switch is used, the operating system will ignore the additional RAM until the /3GB switch is removed. This is because of the increased size of the kernel required to support more Page Table Entries. The assumption is made that the administrator would rather not lose the /3GB functionality silently and automatically; therefore, this requires the administrator to explicitly change this setting.

The /3GB switch allocates 3 GB of virtual address space to an application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header. This switch allows applications to address 1 GB of additional virtual address space above 2 GB.

The virtual address space of processes and applications is still limited to 2 GB, unless the /3GB switch is used in the Boot.ini file. The following example shows how to add the /3GB parameter in the Boot.ini file to enable application memory tuning:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINNT="????" /3GB


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

ViN86
03-03-07, 12:43 AM
Yeah how much is will recognize/take advantage of.

I just found this, which says it only uses 2GB. Anybody know the difference between the 2GB referenced here and the 3.3GB thats shows in windows?



http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx
yea everyone says its supposed to be 4GB, even the motherboard manufacturers.... psshh :rolleyes:

tbh though, you only need 2GB with XP. if you want a lot more, you need to move to a 64 bit OS or windows server 2003 or something.

sillyeagle
03-03-07, 02:48 AM
Its funny how the memory sweet spot in 9x was 128mb, and now just a few years later its 2GB. lol I wonder what we will be using by the time Vista is ready to be upgraded.

CaptNKILL
03-03-07, 08:57 AM
Its funny how the memory sweet spot in 9x was 128mb, and now just a few years later its 2GB. lol I wonder what we will be using by the time Vista is ready to be upgraded.
Heh, 512Mb or at least 256Mb was the sweet spot in 9x for me.

Man, I remember back when upgrades were all cool numbers like that. 64mb, 128Mb, 256Mb...

Now everything is all even gigs. :p

No one cares that its 1024mb or 2048mb... those extra 24 or 48mb don't mean squat anymore. :p

hokeyplyr48
03-03-07, 09:57 AM
can vista 32-bit recognize all 4 gigs, or does it have the same problem?

Dazz
03-03-07, 10:09 AM
768MB was great in windows 9x.

Rytr
03-03-07, 12:06 PM
can vista 32-bit recognize all 4 gigs, or does it have the same problem?

Probably limited to around 3GB. I have not tried 4GB with Vista yet so I don't have any results for mine but I would think it would be about the same as I experienced in XP which was up to 3.3GB. Note the following which I pulled off the net some time ago...don't remember where but it gives the general explanation.

"The PCI memory addresses starting down from 4 GB are used for things like the BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and video/graphics cards. The BIOS takes up about 512 KB starting from the very top address. Then each of the other items mentioned are allocated address ranges below the BIOS range. The largest block of addresses is allocated for today’s high performance graphics cards which need addresses for at least the amount of memory on the graphics card. The net result is that a high performance x86-based computer may allocate 512 MB to more than 1 GB for the PCI memory address range before any RAM (physical user memory) addresses are allocated."

Hapatingjaky
03-03-07, 04:31 PM
768MB was great in windows 9x.

Windows 98 will recognize 768MB it will never use it, the max Windows 98 can allocate was 512MB. A good way to test this was using the memory tweak in Quake 2 or Quake 3 so the game would allocate more memory, only issue was anything over 512MB would give you an error, insufficent memory allocation failed.

You can use the reg tweak though which worked fine. I said screw it and moved to Windows 2000 Professional and never had an issue again with memory.

stncttr908
03-03-07, 09:05 PM
Theoretically, 2^32 = 4294967296 bytes = 4GB. :D

Irate
03-03-07, 09:25 PM
So, how would Windows perform if you ran it with a VM on a Linux install using 4GB of RAM? Excuse me for asking this, but I have no way to test this scenario out.

Dav007
07-26-09, 08:02 PM
I remember when 4k and 16k were large amounts of memory. lol

pakotlar
07-26-09, 08:16 PM
Do you mean how much it can actually use or how much can it recognize? I believe that it can recognize up to about 2.8GB. At least in 32-bit mode.

A little over 3GB actually there eagle, Very Large aware games can use more. So GTA4 can use the full 4GB in XP.

pakotlar
07-26-09, 08:20 PM
Yeah how much is will recognize/take advantage of.

I just found this, which says it only uses 2GB. Anybody know the difference between the 2GB referenced here and the 3.3GB thats shows in windows?



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

Hmm not sure about this. Maybe its an XP limitation.

ex: http://stackoverflow.com/questions/181050/can-you-allocate-a-very-large-single-chunk-of-memory-4gb-in-c-or-c/181107

Theoretically a VLA aware game should be able to address memory up to 4GB. Anyone have information to the contrary?

hemmy
07-26-09, 08:28 PM
A little over 3GB actually there eagle, Very Large aware games can use more. So GTA4 can use the full 4GB in XP.

Pretty sure individual programs are limited to 2gb in 32bit environments

Thunderbolt56
07-27-09, 08:33 AM
XP and Vista will both recognize the same amount of RAM provided they are both the 32 bit versions. I've run both and they both recognize 3.25GB of the 4GB I had in them. The RAM recognized is not OS-dependant (i.e. XP, Vista, Win7), but it IS dependant on whether each OS is 32 or 64 bit.

All three OS's will recognize more than 3.25GB if they run 64 bit.

harl
07-27-09, 08:52 AM
Xp can use up to 4GiB of memory but that includes RAM in devices like graphics card.
That's why the available ram is different,for example with a 2GiB graphic card Xp will show less than 2 GiB of RAM

qube
07-27-09, 10:13 AM
Why bump a old thread like this :headexplode:

zingzong
07-27-09, 10:47 AM
A little over 3GB actually there eagle, Very Large aware games can use more. So GTA4 can use the full 4GB in XP.

Do you purposefully stalk Xion just to start arguements with him? I mean really.........get a life. This thread is ancient and yet your trying to pick a fight with him over something so old.

bob saget
07-27-09, 12:30 PM
Please tell me how a child like this stays around here long enough to accumilate 22,000+post without ever getting banned?

Doesnt say much about the admin around here.

But you never pick fights :wonder: