4GB DDR2 on WinXP 32bit - question

[MedicD]

Hey, I just got this new pc, duo core 2 E6600, 4GB DDR2 800, EVGA 8800GTX 768MB GDDR3.

It's awesome, fastest thing I have ever used, but Windows can only see 2.75GB (bios sees all of it). I looked it up online and most posts agreed with each other that WinXP 32bit can only see about that much, never a full 4. The windows site says that you will never see that other ram you got...but...all the sites also say that windows reserves 1 or 2 GB. It never says if other programs have access to that extra 1.25GB or not, or if I will only be able to use 2.75GB forever

[Kinlaadare]

Shortly : it's 2.75 GB for everybody

little longer
If you want to have access to all your memory, you either need a windows 2003 (edition you want) or a x64 windows...
Vista 32bit edition has the same problem...

[Jito463]

It's a limitation of 32-bit operating systems, as Kinlaadare said. However, you should check your BIOS for a "memory remap" option to enable the full 4GB of RAM for Windows. Though again, you will not be able to take full advantage of it with a 32-bit OS anyway. Only 64-bit OS's can utilize greater than 4GB of RAM, and the 32-bit Windows can't really use more than 2GB technically (though certain apps can utilize the remainder).

[MedicD]

hey thanks for the answers, i appreciate it.

This may be a dumb question, but can you run 64-bit windows on a duo core 2? I know almost nothing about 64-bit stuff.

[NetSoerfer]

Yes, as Intel's website explains, All Intel® Core™2 Duo processors feature: [...] Intel® 64 architecture

[Jito463]

I forgot to mention, you can edit the boot.ini and make Windows allocate 3GB of the RAM for applications instead of 2GB. In the boot.ini, add /3gb to the command-line parameters. If you do switch to a 64-bit OS (either XP x64 or Vista x64), this is not necessary.

[Nodens]

It's a limitation of 32-bit operating systems, as Kinlaadare said. However, you should check your BIOS for a "memory remap" option to enable the full 4GB of RAM for Windows. Though again, you will not be able to take full advantage of it with a 32-bit OS anyway. Only 64-bit OS's can utilize greater than 4GB of RAM, and the 32-bit Windows can't really use more than 2GB technically (though certain apps can utilize the remainder).

There is a way for an application to address far more than the VAS limitation by using CreateFileMapping() http://msdn2.microsoft.com/En-US/library/aa366537.aspx

[Jito463]

Perhaps I'm dense, but I don't see what you're talking about. Care to pinpoint the section you're referring to?

[Nodens]

Sorry mate, I didn't explain it all too well. You can allocate far greater sizes while not mapping it all at once. See this example here

http://blogs.msdn.com/oldnewthing/archive/2004/08/10/211890.aspx

[Jito463]

I see what you're saying. I think we're both saying the same thing, just differently. Applications can be coded to use more than 2GB of RAM in a 32-bit OS, though the OS itself can still only use 4GB of RAM total.

[Nodens]

Indeed. Exactly like that

[FISKER_Q]

Windows XP can fine deal with up to 4GB memory, however that includes all memory.

This means your video card and whatever will go towards that limit.

Before SP1 though you could deal with a lot more memory, but since it might cause problem with programs it was removed again, so now you need a 64-bit version of windows to use more than 4GB.

[Jito463]

Umm, no. Video card RAM has NOTHING to do with system RAM. And SP1 made no changes in the amount of RAM Windows could handle, it's a 32-bit limitation. Please don't post if all you're going to do is spread crap.

[FISKER_Q]

Umm, no. Video card RAM has NOTHING to do with system RAM. And SP1 made no changes in the amount of RAM Windows could handle, it's a 32-bit limitation. Please don't post if all you're going to do is spread crap.

It isn't. Video Memory has to be addressed just as normal memory has to, as well as many other kinds of memory that needs to be addressed within windows.

With a normal 32-address space you can only address 4GB memory, and that's all kinds of memory.

Before SP1 or SP2(I don't remember) you could address "more than 4GB" by using a PAE driver, unfortunately some software couldn't handle it, and even the software that could handle it would maximum be able to use 4GB of memory, regardless of how much memory you had.

If you want to read more about the subject there is:

http://www.codinghorror.com/blog/archives/000811.html

[FISKER_Q]

Oh and btw, in regards to MedicD's number, this is likely the scenario:

768 MB from the video adapter.
512 MB from the motherboard. (What it's used for i don't know, but most motherboards these days map 512MB ram, which if hitting the 4GB barrier makes the RAM accessible, lower)

I myself have 3,25GB memory free out of 4GB with a 256MB 7800 and, again the same 512MB allocated to the motherboard.