Vista and RAM

[Jay A]

I have a Gateway desktop which came with 2 512mb ram chips. I have disabled
the onboard graphics chip and am using an nvidea based 8600GT card with
256mb on it. I replaced the 512 system ram chips with 2 2gb chips giving
myself a total of 4gb of ram.

However, even though my bios reports the 4gb of memory, Windows Vista only
reports 3.25. I have read someplace that Vista does not report memory
correctly or something to that effect. Can someone please explain?

 

[Charlie42]

However, even though my bios reports the 4gb of memory, Windows Vista only
reports 3.25. I have read someplace that Vista does not report memory
correctly or something to that effect. Can someone please explain?

http://support.microsoft.com/kb/929605

Charlie42

 

[Andre Da Costa[ActiveWin]]

If you are running a 32 bit version of Windows Vista, you will see
limitations in how much RAM it recognizes which is usually around 3.1 to 3.2
GBs. If you want it all to be recognized, I recommend you move to Windows
Vista x64.

 

[Ken Blake, MVP]

However, even though my bios reports the 4gb of memory, Windows Vista only
reports 3.25. I have read someplace that Vista does not report memory
correctly or something to that effect. Can someone please explain?

No, that's not the reason. Here's my standard message on this subject,
which I've posted in these newsgroups many times:

"All 32-bit versions of Windows (Vista as well as XP), even though
they have a 4GB address space, can only use *around* 3.1GB of RAM.
That's because some of that space is used by hardware and not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but is
usually around 3.1GB."

Note that the hardware is using the address *space*, not the actual
RAM itself. The rest of the RAM goes unused because there is no
address space to map it too.

 

[Jay A]

OK, well I guess it's still an advantage over installing just 2gb.

So matter how much ram I install, it will only address up to about 3.2gb?
Even if I replace this with 8gb of ram?

That's because some of that space is used by hardware and not <
available to the operating system and applications. <

Well, if some of it is used for hardware, then why is it that with only 1gb
of ram installed, windows reports just about 1gb? Or with 2gb installed, it
reports just about 2gb? This almost seems to imply that if more ram is
installed, Vista will use a greater percentage of it for hardware. Is this
so?

 

[jorgen]

OK, well I guess it's still an advantage over installing just 2gb.

So matter how much ram I install, it will only address up to about
3.2gb? Even if I replace this with 8gb of ram?

Yes. Microsoft has capped how much memory they support in their desktop
editions

 

[PvdG42]

Yes. Microsoft has capped how much memory they support in their desktop
editions

The 4 gig limitation applies *only* to 32 bit Windows versions. The 64 bit
versions of Win XP and Vista will use 4, 8, ...
gig of memory.

 

[jorgen]

The 4 gig limitation applies *only* to 32 bit Windows versions. The 64
bit versions of Win XP and Vista will use 4, 8, ...
gig of memory.

Of course. But even some of the 64-bit editions are capped lower than others

 

[Jay A]

I'm OK with the 3.2gb. I just wanted to know if what I was seeing is normal.

I can't see going to 64 bit Vista. Not many applications for one, plus I
can't see having to worry about hardware and drivers and all just to be able
to take advantage of more memory.

 

[Ken Blake, MVP]

OK, well I guess it's still an advantage over installing just 2gb.

Maybe, maybe not.

Despite the number of people who continually repeat "more RAM is
better," that's true only up to a point. And that point depends on
what apps you run. If you have enough RAM so that the page file is
seldom if ever used, more RAM does nothing for you.

For most people running a range of common business applications under
Vista, 2GB is enough to keep them from using the page file, and any
more is wasted. Only those who run particularly
memory-hungry applications (typically photo- or video-editing) need
more.

So matter how much ram I install, it will only address up to about 3.2gb?
Even if I replace this with 8gb of ram?

Correct.



Well, if some of it is used for hardware, then why is it that with only 1gb
of ram installed, windows reports just about 1gb? Or with 2gb installed, it
reports just about 2gb? This almost seems to imply that if more ram is
installed, Vista will use a greater percentage of it for hardware. Is this
so?

No. Reread the following paragraph, which you snipped from your quote:

"Note that the hardware is using the address *space*, not the actual
RAM itself. The rest of the RAM goes unused because there is no
address space to map it to."

Assuming that your hardware needs .8GB of address space and you have
2GB of RAM installed. 2 + .8 totals 3.8GB, and that all fits into the
4GB address space without a problem. But 4GB of RAM + .8GB for the
hardware totals 4.8GB, and that does *not* fit into the 4GB address
space.

 

[Michael Palumbo]

OK, well I guess it's still an advantage over installing just 2gb.

So matter how much ram I install, it will only address up to about 3.2gb?
Even if I replace this with 8gb of ram?


Well, if some of it is used for hardware, then why is it that with only
1gb of ram installed, windows reports just about 1gb? Or with 2gb
installed, it reports just about 2gb? This almost seems to imply that if
more ram is installed, Vista will use a greater percentage of it for
hardware. Is this so?

You're missing it totally.

The address space is mapped to hardware, but it really has nothing to do
with actual RAM.

The hardware address mapping is a 'top-down' approach, no matter how much
RAM you have installed, the hardware starts getting addressed from the
highest address(s) the OS is capable of, regardless of the amount of RAM
installed.

The hardware doesn't actually use any RAM, it's simply accessed using the
memory addresse(s) it's assigned.

The problem is that a 32 bit OS can only address a TOTAL of 4 GIGS, Even if
you only have 128 megs of RAM installed the OS can still address 4 GIGS of
RAM.

So, for example, if you have hardware that in total needs 512 megs of
address space, and you have 1 gig of RAM, the 512 megs of addresses are
taken from the TOP of the 4 GIG address space, well outside of your
available physical RAM. If you have 2 gigs, same thing, since the address
space will be taken from 3.5 gigs to 4 gigs it simply will not effect your
available RAM in the system, all of the RAM will receive proper addresses
and will be available to the system for use.

Now, again, the problem is that a 32 bit OS can ONLY address a TOTAL of 4
gigs, so if you have 4 gigs of RAM installed, the hardware will STILL use
the addresses available from 3.5 to 4 gigs. Since these addresses are no
longer available to address the REAL RAM installed on your system that RAM
can't be used.

I hope this clears thing up for you, I thought it was explained (about 100
times) already in the group(s) and in the links provided (Google is a
wonderful thing as well).

Mic

 

[Tim Slattery]

If you're running 32-bit Vista, you have a 32-bit (4GB) address space.
That has to be used to access video RAM, BIOS, etc. as well as system
RAM. So you won't be able to use all 4GB of RAM. If your motherboard
will handle 8GB, you won't be able to see more than about 3.2GB unless
you're running 64-bit Vista. See
http://members.cox.net/slatteryt/RAM.html

 

[Ken Blake, MVP]

Assuming that your hardware needs .8GB of address space and you
have
2GB of RAM installed. 2 + .8 totals 3.8GB, and that all fits into the
4GB address space without a problem. But 4GB of RAM + .8GB for the
hardware totals 4.8GB, and that does *not* fit into the 4GB address
space.

--
Ken Blake, Microsoft MVP Windows - Shell/User
Please Reply to the Newsgroup

I'm pretty sure that 2 +.8 = 2.8.

You picked what appears to be a very old message to reply to, but
yes, 3.8 seems to be a typo for 2.8.

However the point remains correct--2.8GB fits in a 4GB address space.

 

[Ken Blake, MVP]

Looks like the old message was from 1/22/2008. Regardless, I'm confused
enough about 64 bit ops' ram usage without throwing numerical typos into
the mix.

My apologies. Obviously, I didn't make the typo on purpose.

My current issue: Vista 64 on MSI 7093 main board, 8600gt, 4400+cpu,
4gb ram installed, bios shows 3.42 mb ram. I guess it's a bios problem.
Going to try some video memory allocation settings. Will post results
later.

The message above was about 32-bit Vista, not 64-bit. The issue
described doesn't pertain to the 64-bit version.

Do you have on-motherboard video, or a separate video card?