X60 C2D + 4GB RAM + Windows XP Pro x64 = 3GB RAM in the OS

[brosen]

I just installed 2 x 2GB DIMM and instaled Windows XP Professional x64 in order to get full advantage of the 4GB of RAM, nonetheless the Windows OS only shows 3GB ?????

It is the same like Windows XP Pro x86, I do not get it ?????

The BIOS setup of the X60 Core 2 Duo 7200 shows 4GB, any idea what could be wrong ?, thanks

[smugiri]

To get use all the RAM on other versions of Windows, you need to add a switch to boot.ini but I am not sure this applies to the x64 version that you are using.

The X60 uses a 32bit processor, right? I am also not sure what Win XP x64 is.

[brosen]

To get use all the RAM on other versions of Windows, you need to add a switch to boot.ini but I am not sure this applies to the x64 version that you are using.

The X60 uses a 32bit processor, right? I am also not sure what Win XP x64 is.

You are right the /3GB switch is ONLY for 32-Bit version.

I have the newest X60 with Core 2 Duo T7200 with an x64 Processor.

Windows XP Professional x64 means the 64 bit version of the OS

[brosen]

I tried with Windows Server 2003 x64 and also shows only 3GB RAM, I do not understand, there is something very WEIRD here ????????

[duffy]

Here's your answer.

http://blogs.zdnet.com/Apple/?p=321

[brosen]

I've tried:

- Windows XP Pro x64
- Windows Server 2003 x64
- Windows Vista x64
- Suse Linux 10.1 x64

And nothing, it seems some king of HARDWARE limitation, all of them recogize ONLY 3GB, so why the Laptop support upto 4GB ?, I really do not understand

[duffy]

Try reading my post above. Unless you like wasting time installing OS's.

[kskim91]

It's the old 945 chipset problem. You can plug in 4GB, hence the 4GB support, but you cannot use them all. I got around 3.2GB. The 945 chipset cannot remap the physical memory above the 3GB addresses. If I remember correctly the address above 3GB is used by the pci and other devices. More recent chipsets get around this problem by having an option in the bios that allows the physical memory to be remapped above those used addresses. I also learned this the hard way with a 945G motherboard.

This is regardless of whether you are using a 64bit OS or not and as it is a 945 chipset design limitation there is no work around for this.

[tomh009]

I've tried:

- Windows XP Pro x64
- Windows Server 2003 x64
- Windows Vista x64
- Suse Linux 10.1 x64

And nothing, it seems some king of HARDWARE limitation, all of them recogize ONLY 3GB, so why the Laptop support upto 4GB ?, I really do not understand

The Napa platform (ie the Intel 945 chipset) is limited to addressing 4 GB. I think what's happening here is that the top 1 GB is being used for PCI Express and other similar functions, so the X60 (like the MacBooks, too) will only recognize 3 GB. See Kingston's note here:

http://www.ec.kingston.com/ecom/configu ... ysID=28576

Are there any BIOS settings on the X60 that might allow you to move things around?

[tomh009]

Additional confirmation from the tabook endnotes:

31. Maximum memory capacity may require the replacement of standard component with largest supported component available. On the ThinkPad systems with an Intel 945GM or 945PM chipset, even though it is possible to physically install 4GB of memory, the actual amount of memory addressable by an Operating System will be limited to 3GB.