Graphics Aperature Size

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RJ

I have an X800XT 256MB AIW video card on a Asus P4P800E-Deluxe
motherboard with 1 GB of Corsair 2-2-2-5 DDR memory. One of the
settings in the motherboard is "Graphics Aperture Size with settings
of 4, 8, 16, 32, 64, 128, and 256 MB. It defaults to 64MB and I have
left it there but wonder if I should be changing it. Any idea what
this does and what I should be setting it to?
 
RJ said:
I have an X800XT 256MB AIW video card on a Asus P4P800E-Deluxe
motherboard with 1 GB of Corsair 2-2-2-5 DDR memory. One of the
settings in the motherboard is "Graphics Aperture Size with settings
of 4, 8, 16, 32, 64, 128, and 256 MB. It defaults to 64MB and I have
left it there but wonder if I should be changing it. Any idea what
this does and what I should be setting it to?
Click to expand...
Leave it where it is.
The 'point' about the graphics aperture, is that it is a region in the
main memory, that the graphics card can use to store things like texture
maps. It was vital on cards with (say) 32Mb RAM, when doing large 3D
texture maps, where extra storage was needed. However as RAM sizes grew on
the cards, the amount this was used declined. On a card with 256MB, you
could probably set it to 0, but leaving it at 64MB, allows for some
expansion of the texture maps etc., if needed, and is a good safe setting.
You will probably see no difference at all in performance for any of the
setting values.

Best Wishes
 
Unfortunately, the below is not true. I had two games that would run like
a$$ on my system (2.592 Ghz Mobile Athlon, 1GB PC3200, 9800 Pro):
Battlefield 1942: Secret Weapons and BloodRayne (the original console port).
The problems happened at any Graphics Aperture Size setting below 128MB. On
Rage3d a guy performed a variety of tests with different games and found
Graphics Aperture Size setting DID make a difference in frame rate. You
can't just make blanket generalizations about what size to set the Graphics
Aperture Size too.
 
Doug said:
Unfortunately, the below is not true. I had two games that would run like
a$$ on my system (2.592 Ghz Mobile Athlon, 1GB PC3200, 9800 Pro):
Battlefield 1942: Secret Weapons and BloodRayne (the original console
port). The problems happened at any Graphics Aperture Size setting below
128MB. On Rage3d a guy performed a variety of tests with different games
and found Graphics Aperture Size setting DID make a difference in frame
rate. You can't just make blanket generalizations about what size to set
the Graphics Aperture Size too.
Click to expand...

I agree - having recently played Boiling Point (which needs a lot of RAM)
I experienced improved performance going from 128mb aperture to 256mb.
You may find most games dont see any differance but the occasional game
will benefit from adjusting the aperture. Try 128mb and 256mb and see how
you get on.
 
I tested my system last year with various graphic aperture sizes (9800 pro,
Athlon 2800+, 1 gig of ram) and I found that the sweet spot was a graphics
aperture size of 128 mb. 64 megs resulted in a very slight performance hit;
16 and 32 resulted in a big hit. Going from 128 megs to 256 megs resulted
in little or no performance improvement on my system anyway.

JK
 
I know of one "tech demo" that performs significantly better with the
aperture at 256 MB - the ATi Ruby demo. Haven't seen any drawbacks yet. My
suggestion is to set it at 256 MB until you notice graphics anomalies in
games.

Note the setting causes the video card to reserve additional system memory
for textures *only when needed*. When the amount of textures in a game is
not sufficient to spill over from video card memory to system memory, the
system memory is still usable in its entirety for other processes.
 
Roger said:
Leave it where it is.
The 'point' about the graphics aperture, is that it is a region in the
main memory, that the graphics card can use to store things like texture
maps. It was vital on cards with (say) 32Mb RAM, when doing large 3D
texture maps, where extra storage was needed. However as RAM sizes grew on
the cards, the amount this was used declined. On a card with 256MB, you
could probably set it to 0, but leaving it at 64MB, allows for some
expansion of the texture maps etc., if needed, and is a good safe setting.
You will probably see no difference at all in performance for any of the
setting values.

Best Wishes
Click to expand...

Not true a setting of '0' shall turn AGP acceleration off.

Default of 64 or 128 is fine, as you mentioned.

Cheers
Minotaur (8*
 
I always and only as a guestimate set it to whatever the card itself had for
memory. Thinking is that any more than that and there'd be additional
instructions required to set up memory region(s) etc. when data needed
transferring.
 
Taking a moment's reflection, First of One mused:
|
| Note the setting causes the video card to reserve additional system
| memory for textures *only when needed*. When the amount of textures
| in a game is not sufficient to spill over from video card memory to
| system memory, the system memory is still usable in its entirety for
| other processes.

You've got that backward. When you set the aperture to 256, it
reserves that memory *for when it is needed* ... So, whether you need it
or not, it is reserved in advance.
 
Taking a moment's reflection, pjp mused:
|
| I always and only as a guestimate set it to whatever the card itself
| had for memory. Thinking is that any more than that and there'd be
| additional instructions required to set up memory region(s) etc. when
| data needed transferring.

The problem with that model, though, is that there is an inverse
relationship between Aperture Size and video memory. The more video
memory you have, the less aperture you will need. A card with 32 MB of
memory will need a higher aperture setting than a card with 256 MB.

Applying your model to the above, you would have the aperture for
the 32 MB card set for 32 ... and I doubt you would get very good
performance when compared to setting the aperture to 128.
 
Taking a moment's reflection, First of One mused:
|
| Note the setting causes the video card to reserve additional system
| memory for textures *only when needed*. When the amount of textures
| in a game is not sufficient to spill over from video card memory to
| system memory, the system memory is still usable in its entirety for
| other processes.

You've got that backward. When you set the aperture to 256, it
reserves that memory *for when it is needed* ... So, whether you need it
or not, it is reserved in advance.
Click to expand...

Please explain further. These aperture sizes were available when it
was not uncommon for computers to have only 256 MB of RAM. How could
all of the system memory be "reserved in advance" for the use of the
display adaptor?


Ron
 
"mhicaoidh" said:
Taking a moment's reflection, First of One mused:
|
| Note the setting causes the video card to reserve additional system
| memory for textures *only when needed*. When the amount of textures
| in a game is not sufficient to spill over from video card memory to
| system memory, the system memory is still usable in its entirety for
| other processes.

You've got that backward. When you set the aperture to 256, it
reserves that memory *for when it is needed* ... So, whether you need it
or not, it is reserved in advance.
Click to expand...

The AGP aperture is a mapping. It does not have to be backed
with physical memory until needed. The video card doesn't
randomly access the entire AGP aperture, it is under programmatic
control, and if Windows puts a texture in some physical memory,
sets the GART to make a mapping so the video card can get at
the texture, then programs the video card so it knows there
is a texture present, then it gets used. It is up to Windows
to manage the memory, and make sure that a piece of physical memory
holding a texture, is not used for something else.

AGP aperture is an allocation of address space, not an
allocation of actual memory.

http://www.ocfaq.com/forum/printthread.php?t=112&pp=100

As I understand it, setting the AGP aperture to large values,
has some impact on the address space. See figure 9 on PDF
page 118. If you have 4x1GB DIMMs on an 875 based motherboard,
figure 9 shows how setting a large AGP aperture will make less
of the 4GB of memory available to the OS.

ftp://download.intel.com/design/chipsets/datashts/25252502.pdf

Paul
 
Taking a moment's reflection, Paul mused:
|
| The AGP aperture is a mapping. It does not have to be backed
| with physical memory until needed. The video card doesn't
| randomly access the entire AGP aperture, it is under programmatic
| control, and if Windows puts a texture in some physical memory,
| sets the GART ... [snip]

I understand that. But the GART will be bigger when set to 256 than
it will be at 32 (for example), and on a system with limited resources,
this could cause problems. For example, on an older system I had, if I
set to Aperture to 256, the sound card drivers would fail to load.
Setting it back to 128 fixed the problem.
 
Sorry, but no, default of 64 or 128 isn't just fine, it's system/video
card/game specific, nice try though.
 
Because in order to use system memory as texture memory you have to set up
some sort of lookup table that maps system memory to AGP texture memory.
This lookup table eats up memory on practically a 1 to 1 basis. On windows
98SE having a 512MB AGP aperture size eats up significant system resources
even if unused. I'm not sure how XP handles this though.
 
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