It isn't the physical RAM that is the problem. It is the addressing system.
Basically, the system maps everything it needs to a (hate to use the word,
as it's not really accurate) virtual memory place, or address space. This
place can only be 4 GB in size. This includes the RAM, video card, BIOS, and
other hardware that maps itself there. If you have an independant video
card, that will reduce it by the amount of RAM the card has.
Imagine a map of a factory 4 acres in size. You have 4 acres of product
(RAM), but the shelves, equipment and boxes (video card, BIOS, etc.). The
factory can support 4 acres of total space, but only a certain amount is
available for certain things. There is going to be some overhead.
"Scott" <NoSpam-Scott.Xe@GMail.com> wrote in message
> 3.5 GB is the limit of 32-bit OS. My computer claims to take 4 GB RAM so
> it is not much useful to add up to the max. as I have 2 GB RAM on my
> computer. Other parts of computer will use the RAM over 3.5 GB. Is it
> really true on every Vista computer or subject to certain conditions as my
> video card is independent one, not share the system RAM?
> "Cal Bear '66" <email@example.com> 在郵件
> news:2B45189F-BB03-4157-9C20-81C11A155FC4@microsoft.com 中撰寫...
>> It IS a limit of any 32-bit OS.
>> I Bleed Blue and Gold
>> GO BEARS!
>> "mtogni" <firstname.lastname@example.org> wrote in message
>>>I have a brand new pc with Vista Pro and 4Gb of RAM DDR800 on board. BIOS
>>> correctly recognizes the right amount of memory but Windows don't. It
>>> only 3,5 RAM. Am I missing something or it's a O.S. limit?
>>> Thanks in advance.
>>> Michelangelo Togni