Extended RAM available when dedicated to your video/graphics card?

[Brian V]

Hi. I have learned that a person is able to dedicate a certain amount of RAM
to their video/graphics card.

In 32-bit XP and Vista, there is the apparent 4Gb limit on the RAM that is
recognized (or allocated?).

So my question is: If I were to dedicate all the RAM my graphics card would
take to the graphics card (It's a 512Mb possability), or another card I could
install (we'll say 1Gb capacity for the graphics) would my system have 512 Mb
(or 1Gb) of RAM for the graphics and 3.5Gb (or 3Gb) for the rest of the
processes?

Or would I have 512 Mb for the video card and be able to put up 4 Gb for the
system equalling 4.5 Gb total? (or in the other case 1Gb for the video card
and 4Gb for the system equalling 5Gb)?

I think I got that math right. But this potentially deals with overclocking?
I am kind of aware of overclocking (it's even in the motherboard manual!),
but do not want to do this now. I need more experience, and a computer tower
to deal with the heat, etc. I do say that the warrenty is long over, so it
will not be voided with any overclocking anyways.

 

[Daave]

Hi. I have learned that a person is able to dedicate a certain amount
of RAM to their video/graphics card.

Only if it is onboard video. That is, if your motherboard contains
onboard graphics, it automatically uses up potentially precious RAM.

Now if you have a *separate* graphics card, it contains its own
processor and RAM (much more efficient!). Here is an example (click the
Specifications tab):

http://www.newegg.com/Product/Product.aspx?Item=N82E16814130339

The memory referenced has *nothing* to do with RAM.

What is the make and model of your motherboard and graphics card? (Or
are you referencing the Acer Aspire E380 mentioned in another thread?)

In 32-bit XP and Vista, there is the apparent 4Gb limit on the RAM
that is recognized (or allocated?).

So my question is: If I were to dedicate all the RAM my graphics card
would take to the graphics card (It's a 512Mb possability), or
another card I could install (we'll say 1Gb capacity for the
graphics) would my system have 512 Mb (or 1Gb) of RAM for the
graphics and 3.5Gb (or 3Gb) for the rest of the processes?

As said above, if you have a separate graphics card, it has its own
memory and will not use *any* RAM (other than for hardware addressing).
And there is no "dedicating." So if you have 4GB of RAM and a separate
graphics card that has 512MB of _its own_ memory, that's what you got!
Apples and oranges.

Depending on how you plan on using your system, 512MB to 1GB of RAM is
probably all you need for XP. (Vista and 7 require more). It is only for
people who use memory-intensive programs (like graphics or video
editing) that more RAM will be useful. And for 32-bit XP (or *any*
32-bit OS for that matter), 3GB is practically the highest you can go.
That is, although your motherboard will permit you to install 4GB of
RAM, Windows will wind up using only 3.2GB or so due to hardware
addressing and the limitations of 32-bit architecture.

Or would I have 512 Mb for the video card and be able to put up 4 Gb
for the system equalling 4.5 Gb total? (or in the other case 1Gb for
the video card and 4Gb for the system equalling 5Gb)?

There is no "total RAM." These are _different types_ of memory: one for
the mobo/PC and one for the graphics card.

I think I got that math right. But this potentially deals with
overclocking? I am kind of aware of overclocking (it's even in the
motherboard manual!), but do not want to do this now. I need more
experience, and a computer tower to deal with the heat, etc. I do say
that the warrenty is long over, so it will not be voided with any
overclocking anyways.

Overclocking is completely different! It's not recommended for most
users. Certain advanced users (usually gamers) like to set their CPU's
clocks higher than the manufacturer's recommendations for an extra boost
of performance. And yes, you really need to know what you are doing with
regard to heat dissipation!

HTH.

 

[Paul]

Hi. I have learned that a person is able to dedicate a certain amount of RAM
to their video/graphics card.

In 32-bit XP and Vista, there is the apparent 4Gb limit on the RAM that is
recognized (or allocated?).

So my question is: If I were to dedicate all the RAM my graphics card would
take to the graphics card (It's a 512Mb possability), or another card I could
install (we'll say 1Gb capacity for the graphics) would my system have 512 Mb
(or 1Gb) of RAM for the graphics and 3.5Gb (or 3Gb) for the rest of the
processes?

Or would I have 512 Mb for the video card and be able to put up 4 Gb for the
system equalling 4.5 Gb total? (or in the other case 1Gb for the video card
and 4Gb for the system equalling 5Gb)?

I think I got that math right. But this potentially deals with overclocking?
I am kind of aware of overclocking (it's even in the motherboard manual!),
but do not want to do this now. I need more experience, and a computer tower
to deal with the heat, etc. I do say that the warrenty is long over, so it
will not be voided with any overclocking anyways.

One thing you may be missing in these discussions, is the difference between
"motherboard built-in graphics" and how a separate added graphics card does it.

If you install a separate graphics card, many of those have their own memory chips
on board. That memory has to be addressable somehow, if the processor is going
to be able to access it.

Built-in graphics (inside the chipset on the motherboard), "steals" system memory.
If you look in the BIOS, there may be a setting as to how much memory you allocate
to the build-in graphics. Maybe it spans from 4MB to 256MB for example.

Say I had 1GB of RAM installed in the computer, and I set the BIOS to allocate 4MB
to the built-in graphics for it to use. Once I get in Windows, it is going to
show (1024MB - 4MB = 1020MB) or less as free memory. If I bumped up the BIOS
setting of a static chunk of memory to 256MB, the OS will see 768MB as free
for other purposes. By allocating 25% of the memory to the build-in graphics,
I'm taking quite a hit on free memory.

If a computer has built-in graphics, and the user adds a graphics card, then
just maybe, the built-in graphics can be disabled. A person could enter the
BIOS and set the allocation to the built-in graphics to zero. Or perhaps,
on some BIOS, when the BIOS detects an installed add-in video card, it
automatically disables the built-in graphics. In that case, then the whole
1GB of system memory would be available to the OS. If there weren't any other
issues (like limited address space), then the OS may report "1024MB free".

So there are options, as to how graphics can use memory. In some cases,
separate memory is provided for the graphics to use, and it doesn't have
to "steal" system memory. In other cases, the graphics "steals" memory
from the main memory pool, and the allocation may be static and unchanging.

There are also reasons for dynamic allocations of memory, such as might
happen when playing a game. When the game play is finished, the memory
would be returned to the system. So we don't have to worry about that
quite as much.

With no graphics card installed in the PCI Express x16 slot of your
particular motherboard, it may work like this.

CPU ---- dual channel
| ---- memory subsystem
|
Video card slot X---MCP61
(Empty) built-in graphics ("steals memory")

Now, install a video card in the PCI Express slot:

CPU ---- dual channel
| ---- memory subsystem
|
PCI Express Video Card X---MCP61
(has own memory) built-in graphics (disabled)

In the second case, the CPU needs to address its own (dual channel) memory,
as well as address the PCI Express Video Card memory. The total address
space limitation, as provided by WinXP 32 bit, is 4GB at the moment.

To make yet another example, let's use the second case again, and install memory,
then check how much is "free" while using WinXP 32 bit as the OS. I'll install
a graphics card that has 1GB of its own memory (such as a recent ATI video card).

CPU ---- 2GB
| ---- 2GB
|
PCI Express Video Card X---MCP61
(1GB private memory) built-in graphics (disabled)

The OS will report roughly "2.75GB free". Why does it do that ? The
system buses, including that graphics card, need 1.25GB of address space.
The OS has an address space of 4GB. The remainder is used to manage the CPU
memory. And that will be somewhere around 2.75GB or so. So 1.25GB of the
memory connected to the processor, simply isn't addressable and cannot
be accessed. It still draws power. It still has random contents. But
no program can reach that 1.25GB chunk of memory on the side of the
CPU. If I switch to a 64 bit OS, all of it can be used.

Is the 1GB of memory on the PCI Express Video Card doing useful work ?
Only when gaming, and even then, some games may not use all of it. You
have to research game usage, to decide whether a 512MB video card or
a 1GB video card is the right purchase.

Paul

 

[Brian V]

Excellent excellent excellent. I got some more information I needed.

The graphics card is on board. I would have to try and disable it. I plan on
getting a PCI express x16 slot filled. My system can handle a NVIDIA 9000
series (somwehere in there). Not yet though. I'm still researching.

I know some of my questions are redundant, but I have trouble expressing
what I am thinking sometimes, or take another few days to clear it up and add
more.

The next question is: Some graphics cards apparently require DDR3 memory. My
motherbaord handles DDR2. I think DDR3 is newer. Can I fit DDR3 onto my mobo?
Or are the slots different than DDR2 (just like DDR2's are different than
those before)? I talked to a guy at work and he said he ignores some of the
specs sometimes. I think that is dumb, but I believe sometimes a person can
get away with what my co-worker does

Can I run a graphics card in the PCI express slot that requires DDR3 RAM
when my mobo uses DDR2? Is it seperate or not like you posted about above?

 

[Paul]

Excellent excellent excellent. I got some more information I needed.

The graphics card is on board. I would have to try and disable it. I plan on
getting a PCI express x16 slot filled. My system can handle a NVIDIA 9000
series (somwehere in there). Not yet though. I'm still researching.

I know some of my questions are redundant, but I have trouble expressing
what I am thinking sometimes, or take another few days to clear it up and add
more.

The next question is: Some graphics cards apparently require DDR3 memory. My
motherbaord handles DDR2. I think DDR3 is newer. Can I fit DDR3 onto my mobo?
Or are the slots different than DDR2 (just like DDR2's are different than
those before)? I talked to a guy at work and he said he ignores some of the
specs sometimes. I think that is dumb, but I believe sometimes a person can
get away with what my co-worker does

Can I run a graphics card in the PCI express slot that requires DDR3 RAM
when my mobo uses DDR2? Is it seperate or not like you posted about above?

We can use one of the diagrams again.

CPU ---- DDR2
| ---- DDR2
|
PCI Express Video Card X---MCP61
GPU built-in graphics (disabled)
|
GDDR3

In that diagram, the DDR2 is the system memory, used by the CPU, and
holds the OS and your programs.

The memory on my example video card, is GDDR3 memory. It is controlled
by the GPU. The CPU can't "see" that memory. The two chunks of memory
are "isolated" from one another. The memory on the video card
could be GDDR3 or GDDR5, and it makes no difference to the rest
of the computer.

What is important, is that the video card connector, match the slot
available on the computer motherboard. If you had a PCI Express video
card, it has a PCI Express connector. Your motherboard has a PCI Express
x16 slot on it, which can handle x1, x4, x8 or x16 sized cards. The
slot is the thing that must be compatible. The RAM type on the video
card is a "non-issue". It doesn't matter.

When you're buying RAM for your computer (the "DDR2" in the diagram),
yes, you have to match the specs of the DIMMs chosen, to the memory
slot type on the motherboard. If the motherboard is designed for
DDR2 RAM, you plug DDR2 DIMM modules into it. That *is* a case of
plugging like to like.

On the video card, the part you match, is the slot type. The
other components held within the video card, are the business
of the video card, and nothing else. In the diagram above,
the GPU talks to its private GDDR3 chips. The CPU only talks
to the GPU. The GPU translates any requests as required. So
the CPU can't "touch" in an electrical sense, the GDDR3
in the diagram. And that is why, when you're buying a video card,
you don't try to make the "GDDR3" = "DDR2" of the diagram.
You can buy whatever video card you want, as long as it has
a matching slot connector to plug into on the motherboard.

HTH,
Paul

 

[Brian V]

Ok great. I can put a higher end graphics card in the computer if I wanted
with DDR3 on-board ram since I have the PCI Express 16 slot. That is the only
slot I'v seen asked for.