AGP Aperature

[Tyler582]

I dont exactly know much about it, but Im gonna change it when i get home from school today. What does it affect? What kinda things need higher size, like a better GPU? To find the right settin do i just experiment?

[Robbiesan]

Here's some info for you:

http://erado.totalwar.org/tech/solutions/perf_agp.htm

http://support.intel.com/support/tec.../aperture2.htm

http://www.viahardware.com/faq/kt7/faqagp.html

http://www.rojakpot.com/Speed_Demonz...rture_Size.htm

[WindWarrior]

I think ATI suggest 64mb but I set mine up to 128mb seem's to work ok.

[eezip]

youre best bet is to try 128mb first. if you have problems then lower it to 64mb. try not to go lower than that.

[dallasstar]

I had mine at 256 working just fine. I lowered it to 128 though because I didn't really see a speed difference and on one site, it showed that 128 works faster than 64 and 256 modes.

[eX-one]

my default was set at 64. Didn't change it until I got 3dmark scores of like 3000 something with my AIW 8500. bumped it to 128 and it jumped to 6000. 256 didn't make any more of a dif tho.

[Soong]

The AGP aprature is how much system memory the AGP controler is allowed to allocate for texture cashing. Set it as high as possable. Setting it to as much memory as you have won't cause your computer to do a tripple backflip while windows buttfruxors it self. Your BIOS/CMOS setup usualy wont let you set it to the full ammount of system memory anyway.

[Gator]

http://www.rojakpot.net/Speed_Demonz...rture_Size.htm

AGP Aperture Size
Common Options : 4, 8, 16, 32, 64, 128, 256

Details

This BIOS feature allows you to select the size of the AGP aperture. The aperture is a portion of the PCI memory address range dedicated as graphics memory address space. Host cycles that hit the aperture range are forwarded to the AGP without need for translation. The aperture size also determines the maximum amount of system RAM that can be allocated to the graphics card for texture storage.

The AGP Aperture size can be set using the formula : maximum usable AGP memory size x 2 plus 12MB. That means that the actual usable AGP memory size is less than half of the AGP aperture size. That's because the system needs a write combined memory area equal to the amount of actual AGP memory (uncached) plus an additional 12MB for virtual addressing.

Note that all this is merely address space, not physical memory used. The physical memory is allocated and released as needed only when Direct3D makes a create non-local surface call. Win95 (with VGARTD.VXD) and later versions use a waterfall effect. Surfaces are created first in local memory. When that memory is full, surface creation spills over into AGP memory and then system memory. So, memory usage is automatically optimized for each application. AGP and system memory are not used unless absolutely necessary.

Now, many people recommend the AGP aperture size should be half of the amount of RAM your system has. However, that's wrong for the same reason why swapfile size shouldn't be 1/4 of the amount of RAM you have in your system. Like the swapfile's size, the required AGP aperture size will become smaller as the graphics card's memory increases in size. This is because most of the textures will be stored on the graphics card itself. So, graphics cards with 32MB of RAM or more will require a smaller AGP aperture than graphics cards with less RAM.

If your graphics card has very little graphics memory, then you should set the AGP aperture size as large as you can, up to half the system RAM. For cards with more graphics memory, you needn't set the aperture size to half the system RAM. Note that the size of the aperture does not correspond to performance so increasing it to gargantuan proportions will not improve performance.

Still, it's recommended that you keep the AGP aperture around 64MB to 128MB in size. Now, why is such a large aperture size recommended despite the fact that most graphics cards now come with large amounts of RAM? Shouldn't we just set it to the absolute minimum to save system RAM?

Well, in the first place, many graphics cards require an AGP aperture of at least 16MB in size to work properly. This is probably because the virtual addressing space is already 12MB in size! In addition, many software have AGP aperture size requirements which are mostly unspecified. Some games even use so much textures that AGP memory is needed even with graphics cards with lots of graphics memory.

And if you remember the formula above, the actual amount of AGP memory needed is more than double that of the required texture storage space. So, if 15MB of extra texture storage space is needed, then 42MB of system RAM is actually used. Therefore, it makes sense to set a large AGP aperture size in order to cater for every software requirement.

Note that reducing the AGP aperture size won't save you any RAM. Again, what setting the AGP aperture size does is limit the amount of RAM the AGP bus can appropriate when it needs to. It is not used unless absolutely necessary. So, setting a 64MB AGP aperture doesn't mean 64MB of your RAM will be used up as AGP memory. It will only limit the maximum amount that can be used by the AGP bus to 64MB (with a usable AGP memory size of only 26MB).

Now, while increasing the AGP aperture size beyond 128MB wouldn't really hurt performance, it would still be best to keep the aperture size to about 64MB-128MB so that the GART table won't become too large. As the amount of onboard RAM increases and texture compression becomes commonplace, there's less of a need for the AGP aperture size to increase beyond 64MB. So, it's recommended that you set the AGP Aperture Size to 64MB or at most, 128MB.

[Soong]

Originally posted by Gator
Blah blah blah.

Dats what I said!

[Gator]

Originally posted by Sooung


Dats what I said!

LOL

[Kizuel]

Well, that's really only for cards with low memory. It doesn't really apply to today's cards with 64megs, and 128megs...because they have enough memory to handle things on their own. The more memory one the card, the less use for a huge apature.

[Gator]

i've made this thread a sticky because I've seen enough people ask about it on many occasions in various forums

enjoy

[DeathKnight]

I've heard that you should normally set it to half your system memory.

[raptora12]

and i noticed omega now tells people useing his drivers to do the same.

[klutzon]

I read somewhere, I can't remember (I would have loved to give you the link), that the AGP Aperture makes a performance difference for the different CPUs.

The AMD line of processors work best with an Aperture of 128MB, while the Intel line work best with 64MB. I'm working on that basis and left mine at 128MB. It doesn't do any harm, so it's fine that way. "If it ain't broke, don't fix it."

[Yeuemmaimai]

the intel document is incorrect about NT resource management

[Soong]

Originally posted by Kizuel
Well, that's really only for cards with low memory. It doesn't really apply to today's cards with 64megs, and 128megs...because they have enough memory to handle things on their own. The more memory one the card, the less use for a huge apature.

A quote from the CodeCreatures Benchmark Minimum Requirements

4. > AGP Aperture size: This benchmark requires a total video memory greater than 128 mega-bytes. This means that if your graphics card has less than 128MB of memory, then you MUST set your AGP Aperture size to 128MB or greater. Anything less than this can result in inconsistent results or stability issues.

Click here then go to Downloads > Benchmark to read for your self

I'm not trying to say this is typical, I'm just showing there are applications out there that still need massive ammounts of memory even by todays standards.

[tindajii]

Ok, dumb question...

How do I check to see what my AGP apature is set to? Is it in the bios? I am assuming the same place is where I will change it.

Tindajii

[quanta!]

Along with all the other AGP settings are. Chip Configuration for the Asus KT266A boards. If you really wanna hack it, you can use WPCREDIT and manually edit the bit register...

I moved from 16MB to 64MB just to get Max Payne to work. 128MB Aperture got me 1000 more 3DMarks. So, 128MB it is! I got the RAM to spend.

[El_Scorcho]

i dont know. i guess it depends on the mother board. i have a 440bx and i had the apaerature set to like 128 for my nvidia card but when i put in my radeon the system didnt start up and i got a loud beep from the computer speaker. after i set it to 64 every thing was smooth.

[Mike G]

Originally posted by Sooung
Setting it to as much memory as you have won't cause your computer to do a tripple backflip while windows buttfruxors it self.

BWAHAHAHHAHAAHHAHAHAAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHHA

wow...that made me laugh for quite a while

[Warcraft III]

I know someone who was fiddling around and didn't know what the AGP aperture was, so he set it to 2GB. The CMOS had to be reset before the computer would boot again.

[badboy]

I cant see where I can set my aparture size I have looked everywhere in the bios??

I have a Asus A7V133 mb

[Kemal]

Weee..so.. i have a 64mb Radeon 8500 and 898mb of ram..so would it be a good idea for me to have it set to 256?

[El_Scorcho]

thats allot of ram ther felller! THATS ALLOT OF RAM I TELLS YIR! JUST DONT GO HURTN NO ONE WITH THAT BIG BUNCH OF RAM YA GOT THER FELLIRS! mIMPP!

[Kemal]

uhuh.............
*backs away very, very, slowly*

[Dalhectar]

Good info...

[Eolis]

Originally posted by El_Scorcho
thats allot of ram ther felller! THATS ALLOT OF RAM I TELLS YIR! JUST DONT GO HURTN NO ONE WITH THAT BIG BUNCH OF RAM YA GOT THER FELLIRS! mIMPP!

LMFAO

[Loibisch]

Just wanted to add that using an AAS of 256MB has helped a whole lotta bunch of people playing GTA III more smoothly, so there is a point in having it set that high if oyu got the RAM to spend (512MB+)

[kb103]

Damn I wish I woulda known this, I've been at 64mb AGP for over a year now