AGP Aperture question

[Tripredacus]

I got a new video card, and I was all stoked about it but suddenly I might have made a blunder! My old video card was an ATI Radeon 9800XP 256MB. My new one is an ATI Radeon X1650 512MB. My concern is that my motherboard has a maximum aperture setting at 256MB in the BIOS. Does this mean I'm only going to be able to use 256MB?

It actually reads in at 248MB, but honestly I bought this card for the chipset, not so much the memory.

[pointertovoid]

The Agp aperture is just a part of the Cpu's address space (and I believe of the mainboard physical Ram, at least when you don't have Fast Write settings for Agp on both the Gpu and the chipset).

So this won't limit the amount of Ram the Gpu can and will use on its card. Typically, the Gpu stores textures locally before playing and gets texels through the Agp in real time.

[Sysdll]

It actually reads in at 248MB, but honestly I bought this card for the chipset, not so much the memory.

What reads 248mb?

Agp aperture only means something if you have applications that use up the 512mb on your video card.

I leave the agp aperture setting at the bios default. 64mb or 128mb on every board I've seen after 2001.

[Zenskas]

One other thing, you won't see any difference between a 256MB x1650 and a 512MB version if they are running at the same speeds. It just doesn't need that amount of memory. Even an x1950PRO (in my new "LAN-BOX") doesn't need 512MB as a 256MB version produces identical performance even in higher resolutions like 1920x1080.

[Tripredacus]

It actually reads in at 248MB, but honestly I bought this card for the chipset, not so much the memory.

What reads 248mb?

PC Mark 05 does on the DirectX Display Device info. It has:

Description Radeon X1650 Series

Manufacturer ATI Technologies Inc.

Total Local Video Memory 516 MB

Total Local Texture Memory 516 MB

Total AGP Memory 248 MB

Which makes me think of another question. I've been leery of using Anti-aliasing for a long time. I haven't tried it in a while (definately not with this or my last card) but it always seemed to bring a performance hit. Can these cards handle AA without making things slower? My only point of reference is that my Voodoo 5500 can use its full AA ability and there is no performance hit.

[puntoMX]

I leave the agp aperture setting at the bios default. 64mb or 128mb on every board I've seen after 2001.

I`ve seen a lot of problems when you set the size under the amount of memory on the video card, so if you use a 256MB card and set the AGP Aperture Size to 128MB it could mess up your system.

Total AGP Memory 248 MB

That looks more like free memory to me, 8MB will be used in "2D mode".

Can these cards handle AA without making things slower?

No you can't change that much, ... I can't explain it so fast... but there are a lot of different ways to apply AA, all depends on how a game-maker (for example) does his AA. If it's only on texture than the performance would not drop that much but on the edges of polygons you will need to buffer more information and process that... I have to dig into it again ., slap me if I'm wrong .

[strel]

AGP apperture size setting stablishes both:

- the video card memory range -not dedicated to texture storage- with no adress translation and faster access

- the rest of the memory range -dedicated to texture storage- with adress translation and slower access.

Doesn't seems to be necessary a high setting, unless you're not using an texture instensive application.

Edited October 10, 2009 by strel

[Zenskas]

Which makes me think of another question. I've been leery of using Anti-aliasing for a long time. I haven't tried it in a while (definately not with this or my last card) but it always seemed to bring a performance hit. Can these cards handle AA without making things slower? My only point of reference is that my Voodoo 5500 can use its full AA ability and there is no performance hit.

Depends on the game you are using it with. In CSS, turning on AA makes it look not much better and doesn't really slow down the performance much. If its an older game you are playing (and your getting a high framerate) and then you turn on AA you probably won't notice a difference in performance as you can't really tell if its running at 150FPS or 100FPS!!!

[puntoMX]

If its an older game you are playing (and your getting a high framerate) and then you turn on AA you probably won't notice a difference in performance as you can't really tell if its running at 150FPS or 100FPS!!!

That's true for sure.

[Tripredacus]

I changed my Aperture to 128MB and I got a measly 2+ FPS average increase on Far Cry 2 benchmark. So it seems OK for now I guess, as long as that extra 128MB is only used once the 512MB is filled up. It may be a couple years before a game comes out that would do that!

[puntoMX]

At that resolution and texture setting yes, just look back to Doom 3 (check out how much that uses, and that years ago) .

[pointertovoid]

Clearer explanation about AGP aperture there:

http://en.wikipedia.org/wiki/Accelerated_G...ntages_over_PCI

That is, AGP aperture is taken from the main memory (not from the graphics card memory) to store textures that the graphics card can access directly.

[TLH]

I was always under the impression that the more card ram you had the less aperture you needed to give it. Basically it's supplementing the gfx card with system ram. It was only really useful when cards had a small amount of ram. The amount of ram in todays systems and cards it doesn't really matter what you set it at I would think, you'll get almost no hit or gain one way or the other.