Why does 32bit only see 3-3.5GB out of 4GB - and what happens to the rest?

Soldato
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12 Jun 2005
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I understand that it does only see 3 - 3.5GB and there is no way to change that, and i know it something to do with the 32bit operating system, but why does that happen, and what happens to the rest?

Also - I remember hearing that Vista 32bit see's all 4GB of the RAM, but does it use it in the same way that 64bit does?
 
It's all about the number of memory addresses available. 32 bit can, in theory, support 4gb or ram, but that's right on the limit of the number of addresses available. In real use, the actual number is less because addresses are needed for other functions as well as standard ram.

Have a read through this.

http://arstechnica.com/articles/paedia/cpu/x86-64.ars/1

Page 2 contains the maths breakdown of why there was a need to move from 32-64 bit.
 
I remember reading somewhere that you can get a free upgrade to vista 64-bit from microsoft if you are on 32 bit. Is this true? You pay something like £8 for the DVD.

Where can i apply for this? I am on Home Premium which came with my Dell Laptop.

(Just realised there are now drivers for my printer :p)

Is it possible to get one with SP1 integrated?

It's all about the number of memory addresses available. 32 bit can, in theory, support 4gb or ram, but that's right on the limit of the number of addresses available. In real use, the actual number is less because addresses are needed for other functions as well as standard ram.

Have a read through this.

http://arstechnica.com/articles/paedia/cpu/x86-64.ars/1

Page 2 contains the maths breakdown of why there was a need to move from 32-64 bit.

Just had a skim-read, i think thats what i was after thanks.
 
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I understand that it does only see 3 - 3.5GB and there is no way to change that, and i know it something to do with the 32bit operating system, but why does that happen, and what happens to the rest?

Also - I remember hearing that Vista 32bit see's all 4GB of the RAM, but does it use it in the same way that 64bit does?

Mine does not show all 4GB , mine shows 3.5 the graphics take the rest , in the bios is showing the full 4GB
 
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i have 4gb + vista64 since vista was released.. but since about 2weeks ago its been showing 3328mb. on the post it shows 4gb... ive reinstalled vista but it's still the same.. i haven't changed or updated the bios..... i would understand if at post it say 3328mb but it doesn't, it got the full 4gb...
 
32-bit memory addressing lets you address up to 4GB of space (work out 2^32 to see for yourself) - but because Windows addresses things other than system memory using the same addresses (e.g. graphics cards and other devices) the maximum addressable system memory in 32-bit versions of Windows is usually around 3.5GB.

The only real way around the problem is to use a 64-bit architecture. Vista SP1 only changes the user interface to report that 4GB of RAM is installed so that people don't assume there's a problem when it reads less than that.
 
I remember reading somewhere that you can get a free upgrade to vista 64-bit from microsoft if you are on 32 bit. Is this true? You pay something like £8 for the DVD.

Only with the retail version of vista, as it came with your laptop, you only have the OEM version, if you laptop has 4GB of ram, they should have installed the 64bit version, if not, its going to cost you a fortune to upgrade to 4GB anyway.
 
Only with the retail version of vista, as it came with your laptop, you only have the OEM version, if you laptop has 4GB of ram, they should have installed the 64bit version, if not, its going to cost you a fortune to upgrade to 4GB anyway.

Ah right so im going to have to buy Vista 64-bit? So I can't borrow a CD off a mate and use my key?
 
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