Ram on a 32bit so

Donaldmac

Member
Hi I was recently told that any more then 4gb of ram on a 32bit os is essentially useless, can anyone shed any light on this?
 
32-bit operating systems can only address up to 4GB of RAM (though you usually only see 3.5GB), so yes, more than 4GB on a 32-bit system is pointless. If you want more than 4GB, you're best to go with a 64-bit OS.
 
A 32 Bit OS will see 4GB, and the seeing only 3.5 GB statement is false. The PC will see 4 GB including vRAM, so if you have a 1 GB GPU, you will have 3 GB of physical RAM. A 2 GB GPU will make windows only see 2 GB of physical RAM. And a 128 MB GPU will let a 32 Bit OS see 3.8 GB, etc. etc.
 
A 32 Bit OS will see 4GB, and the seeing only 3.5 GB statement is false. The PC will see 4 GB including vRAM, so if you have a 1 GB GPU, you will have 3 GB of physical RAM. A 2 GB GPU will make windows only see 2 GB of physical RAM. And a 128 MB GPU will let a 32 Bit OS see 3.8 GB, etc. etc.

That is not the entire truth. It will not see the videoram. It will see a region of mapped address space. How large that space is depends.

There are also several additional factors that come into play when doing the math.
 
Yes, there is a path to vram. My point was that the OS/CPU get to it through a mapped region of address space. That space is usually not as large as the total amount of vram. So your subtraction of vram is a bit off.
 
A 32 Bit OS will see 4GB, and the seeing only 3.5 GB statement is false. The PC will see 4 GB including vRAM, so if you have a 1 GB GPU, you will have 3 GB of physical RAM. A 2 GB GPU will make windows only see 2 GB of physical RAM. And a 128 MB GPU will let a 32 Bit OS see 3.8 GB, etc. etc.

It'll see 4GB huh? Tell that to my old socket 939 board with 4GB of RAM and Win7Pro x64. It only sees 2.75GB.
 
Do you have memory remapping enabled?

Also, you are talking about system ram, unicorn is talking about address space.

I've done the whole memory remap thing. I actually get more ram with it enabled than disabled.
 
The addressable space for almost all 32 bit OS versions of windows is 2^32 = 4GB, regardless of where it comes from. The memory remapping etc is a trick only as it simply makes memory addresses available through virtualisation or over committing.

But to answer this question simply, Windows 32 bit will add up all the memory addresses required, and anything as a subtraction from 4GB will be addressable to system memory.
 
The memory remapping etc is a trick only as it simply makes memory addresses available through virtualisation or over committing.

I'm not sure what you mean by that, but remapping makes it possible to address the overlapped region of system ram. It will be addressable above 4 G. So any OS that can go beyond 4 G can get to it. With 4 GB installed, 4 GB will be usable.
 
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I'm not sure what you mean by that, but remapping makes it possible to address the overlapped region of system ram. It will be addressable above 4 G. So any OS that can go beyond 4 G can get to it. With 4 GB installed, 4 GB will be usable.

Yes, unless all of it is called at once, as that would cause a OS crash, meaning the extra ram is simply an over commit. Some OS allow over committing (e.g. Linux), Windows generally doesn't for good reason. This is also why some people claim Linux etc uses less RAM, it doesn't it just over commits what it has.

A 32 bit CPU/OS can only address 2^32 no matter what over committing occurs, and they just make the gamble that you will never 'request' all addressable memory at once.

The fact remains, that a 4GB (2^32) is the maximum - however how that is presented to the user is different depending on set up and OS.
 
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