How Does x32 Vista Map a 4GB RAM?

  • Thread starter Thread starter G.Freeman
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G.Freeman

Well, as we all know, x32 editions of anything cannot use a full 4 gigs of
RAM. Instead it uses about ~3.2 gigs of the RAM. I have a laptop with 1 gig
of RAM and Vista Home Premium x32 and a Go6150 integrated graphics card and
i'm thinking about upgrading the RAM to either 2gigs or 4 gigs. Now how does
Vista "choose" the ~3.2 gigs of RAM it uses? Does it randomly choose ~3.2
gigs every time the computer boots or a specific section forever? To
illustrate my question, I've included an anology below.

Imagine that Windows is a person with a bottle of water and the physical RAM
strips are 20 cups, numbered from 1 to 20. The bottle of water can fill about
16 cups. The filled cups represent the used RAM. How will the person choose
which 16 cups to fill? Will he pick 16 cups and stick with them or will he
fill 16 different cups every time he gets a bottle of water (aka the computer
booting up)?

Also since the Go6150 is integrated and the VRAM is mapped into the main
RAM, where will the VRAM be mapped in a 4 gig config? Can it be mapped
outside of the OS's ~3.2 GB or inside it?
 
There are lots of threads on this already.

The range you might see on your computer is between 2.8 and 3.5GB. Bottom
line, there are two of you using your computer; you and the computer.
Please see:
http://support.microsoft.com/kb/929605/
As you can see by this article this is expected behavior in a 32-bit OS. It
isn't that 4GB of memory is not in use, but that what is reported is only
the portion available for user programs.
 
G.Freeman said:
Well, as we all know, x32 editions of anything cannot use a full 4 gigs of
RAM. Instead it uses about ~3.2 gigs of the RAM. I have a laptop with 1 gig
of RAM and Vista Home Premium x32 and a Go6150 integrated graphics card and
i'm thinking about upgrading the RAM to either 2gigs or 4 gigs. Now how does
Vista "choose" the ~3.2 gigs of RAM it uses? Does it randomly choose ~3.2
gigs every time the computer boots or a specific section forever? To
illustrate my question, I've included an anology below.
Click to expand...

Vista doesn't choose. This is done at the hardware level. BIOS will
program the hardware at startup. And that ~3.2G section will be the same
every time.
Also since the Go6150 is integrated and the VRAM is mapped into the main
RAM, where will the VRAM be mapped in a 4 gig config? Can it be mapped
outside of the OS's ~3.2 GB or inside it?
Click to expand...

It will be mapped at the top of your usable RAM, below 4G. So you will
actually get more for your money by using integrated graphics with 4GB
of RAM, because RAM and VRAM share the same address space.
 
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