4GB of RAM, 2.72GB on XP?

[rgarjr]

Wondering how come XP only sees 2.72GB of memory on bootcamp?

 

[steveza]

Because you have installed the 32bit version. There's probably hundreds (thousands?) of posts about this.

 

[rgarjr]

Hehe, yeah I have the 32-bit version of XP in there, but what difference does that make.

 

[steveza]

It's all about the difference between 32bit and 64bit Windows. Basically the non-enterprise 32bit versions cannot access more then 4GB of RAM and they still have to load shared graphics and other stuff into that so you typically see about 3GB available. Unless you specifically need XP you can get the 64bit version of Windows 7 (release candidate) next week. You will have to do a clean install though.

 

[bstreiff]

Wondering how come XP only sees 2.72GB of memory on bootcamp?

A 32-bit operating system (such as XP) is limited to a 32-bit (4GB) memory space.

This memory space is used not just by RAM, but by other devices in your system. A video card will map its own video RAM (which, on modern videocards, can be like 128MB-512MB or more) into the memory space. An ethernet chipset might map 8KB of registers into memory space, etc.

Obviously, this means that you'd be trying to stuff more than you can fit into this address space, so you 'lose' RAM to compensate.

Googling things like '32-bit memory limit' or 'xp 32-bit 4gb' will uncover more information.

 

[rgarjr]

Hmm i didn't even know there was a cap on memory on the OS's. Good info.