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Total System Memory?


Misha

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I am confused about somenthing, the total amount of phyiscal memory that Windows XP Pro. can address is supposed to be 4gb. Now the confusing part to me is, is that ram only? My system consists of 4gb of ram, 2gb video ram, 2 meg L2 cache, and what ever memory the Creativelabs XFI plat. has on it. Is there too much memory for windows to address correctly?

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I am confused about somenthing, the total amount of phyiscal memory that Windows XP Pro. can address is supposed to be 4gb. Now the confusing part to me is, is that ram only? My system consists of 4gb of ram, 2gb video ram, 2 meg L2 cache, and what ever memory the Creativelabs XFI plat. has on it. Is there too much memory for windows to address correctly?

naa its only pertaining to system ram, as for video ram and so forth, they run on a seperate chip

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  • 3 weeks later...

Total available RAM to XP is equal to 4GB - (Total RAM of cards, bios, roms). If you have a 512MB video card with 4GB of system ram, you will only have 3.5GB available in Windows XP. There's a large article on [H]ard|Forum that explains the problem in depth. Also, here's an official microsoft doc about it too.

There are two ways around that problem. Run Windows XP 64-Bit (or another 64-bit OS like Vista) on 64-Bit hardware OR run Windows XP 32-Bit using PAE (Physical Address Extension) on Intel PAE compatible hardware (CPU + motherboard).

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Total available RAM to XP is equal to 4GB - (Total RAM of cards, bios, roms). If you have a 512MB video card with 4GB of system ram, you will only have 3.5GB available in Windows XP. There's a large article on [H]ard|Forum that explains the problem in depth. Also, here's an official microsoft doc about it too.

There are two ways around that problem. Run Windows XP 64-Bit (or another 64-bit OS like Vista) on 64-Bit hardware OR run Windows XP 32-Bit using PAE (Physical Address Extension) on Intel PAE compatible hardware (CPU + motherboard).

that only happens if you have gart drivers.. ie an AGP card :P

doesn't happen with PCI-E, because pci-e doesn't use gart.. it allows the grfx card to access windows ram, but it is shared and only when necessary.

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that only happens if you have gart drivers.. ie an AGP card :P

doesn't happen with PCI-E, because pci-e doesn't use gart.. it allows the grfx card to access windows ram, but it is shared and only when necessary.

Sorry, but it DOES occur with PCI-Express video cards as well.

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but its ATI..lol, j/k Yeh Im a Nvidia man...
Not another fan boy... :rolleyes:

:P

What a bloody waste of money. I really feel sorry for people out there who think they can only be happy with something like that. Hell, I'm using a GeForce 6800GS and HL2, BF2, FEAR, COD2, Oblivion, I've had good framerates on all of them.

"OMFG, where's my 150 FPS!?"

"60 FPS is smooth. Start appreciating what you've got.

Edited by Jeremy
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The physical address space of the IA32 architecture is 4Gb, but the upper 1Gb is usually reserved for memory-mapped I/O, leaving 3Gb of RAM available.

Above 3Gb you'll need PAE as alluded to above.

Video memory is not directly addressable to the CPU, only to the GPU. The graphics card maps an aperture into the upper 1Gb; that aperture may be the size of the entire VRAM if there is sufficient space, or only a portion of it if there is large amounts of VRAM.

Total available RAM to XP is equal to 4GB - (Total RAM of cards, bios, roms). If you have a 512MB video card with 4GB of system ram, you will only have 3.5GB available in Windows XP
This is partially correct. With PAE enabled you will have access to the entire 4Gb of RAM, the 512Mb of VRAM doesn't affect anything as it's probably going to be mapped somewhere in the now-64Gb physical address space.
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Total available RAM to XP is equal to 4GB - (Total RAM of cards, bios, roms). If you have a 512MB video card with 4GB of system ram, you will only have 3.5GB available in Windows XP
This is partially correct. With PAE enabled you will have access to the entire 4Gb of RAM, the 512Mb of VRAM doesn't affect anything as it's probably going to be mapped somewhere in the now-64Gb physical address space.

I wasn't quite clear, but that was what I meant, I was refering to 3.5GB available without the use of PAE.

I would imagine that performance would be better using a true 64 bit memory map vs using PAE?

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