The 3,5 GB RAM limit of Windows

[studio.dmd]

Hello, I need an advice:

OS: Windows XP Pro SP2 32 bit
MB: Asus Maximus Formula
CPU: Intel Q6600 2400 MHz.
Bus: 1066 MHz.
Ram: 4 modules of Kingstone 1 GB, model KHX8500 D2K2/2GN (two couples).

Using diagnostic programs it seems that windows can't see more than 3,something GB of RAM, and that with some kind of guile it can see up to 4 GB, but not as "real" RAM, I couldn't explain.

I heared that there is a patch to let Windows phisically see 4 GB of RAM. Do you know where can I find it?

Thank you.

 

[ddrueding]

The only way To see more RAM is to use a 64 bit OS.

 

[studio.dmd]

ok

But I don't want see more than 4 GB of RAM. I only want to exceed the 3,1-3,5 GB limit to let windows see 4 GB of ram, NOT MORE!

The 32 bit limit is at 4 GB, but windows for other reasons has got some difficulties to reach the 4 GB limit.

 

[sdbardwick]

Look here for some info. There are many other more detailed sources of information. Basically, it is not a Windows problem as much as a x86 problem.

 

[studio.dmd]

ok

I'll have a read. Thank you.

 

[sechs]

Look here for some info. There are many other more detailed sources of information. Basically, it is not a Windows problem as much as a x86 problem.

As the comments in the link point out, that's really false.

Every relatively recent x86 processor (since, what, Pentium II days?) will allow the operating system to address more than 4GB of memory. Until SP1, 32-bit Windows XP could do this; server versions continue to have this ability.

This is to say that this is a actually a feature. At least in Microsoft-speak.

 

[Bozo]

From my limited experiance with 4GB systems, it seems the motherboard is the problem.
Gigabyte and Supermicro motherboards allow the operating system to "see" (use??) all 4GB. Intel and Asus motherboards limit it to ~3.5GB. Don't have a logical explanation, but that is what I observered using these motherboards.

Bozo :joker:

 

[studio.dmd]

ok

Thank you Bozo and others.
bye.

 

[jtr1962]

Gigabyte and Supermicro motherboards allow the operating system to "see" (use??) all 4GB. Intel and Asus motherboards limit it to ~3.5GB. Don't have a logical explanation, but that is what I observered using these motherboards.

Going by my brother's new system, the motherboard certainly "sees" all of the 4GB prior to booting (It says 4194304K available RAM-actually a little less than that due to some holes between 640K and 1024K). However, in XP there is anywhere between 2.75 and 2.93 GB available to the OS, depending upon how much RAM I give the onboard video. I have little doubt the motherboard would allow all of the 4GB to be used by either a 64-bit OS, or a 32-bit one with proper PAEs. However, PAE is crippled in XP, so less is available.