ANYONE know what AGP Apeture means?

By Mtyson8 ยท 10 replies
Dec 22, 2005
  1. ANYONE know what AGP Apeture means? Whats the difference if I set it at 64MB, 128MB or 256MB??? Do you set it to the amount of RAM on your board?? Is it faster if I set the AGP Apeture from 128-256MB?? :eek:
  2. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    Its basically a certain amount of ur RAM that is allocated to storing textures for games. The larger it is, the better is ur performance. Yes it will get faster as u increase the size. It can only be a maximum of 256 MB, no matter how much RAM u have.
  3. Kev_Boy

    Kev_Boy TS Rookie Posts: 23

    I would just like to clarify, it'll use your system memory when the RAM on the video card is full otherwise it will, quite obviously perhaps, not use any system memory.
  4. Mtyson8

    Mtyson8 TS Rookie Topic Starter

    Oh ok thanx. So if I set it at 256MB, im allocating 256MB for textures if they run over the memory on my board? So, if I play an old game, like Doom 1, itll basically never tap into my ram because the game will never use all of the graphics memory? Ill have to set it to 256 for Call of Duty 2 them, cause that game gets choppy when more soldiers are on the map even with a X800/Geforce 6800 or better.
  5. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    Yeah that should fix it. Dramatic performance increases are quite possible, as in my case.
  6. Arcanum

    Arcanum TS Rookie Posts: 181

    AGP aperture does two things. It selects the size of the AGP aperture and it determines the size of the GART (Graphics Address Relocation Table).

    The aperture is a portion of the PCI memory address range that is dedicated for use as AGP memory address space while the GART is a translation table that translates AGP memory addresses into actual memory addresses which are often fragmented. The GART allows the graphics card to see the memory region available to it as a contiguous piece of memory range.

    Host cycles that hit the aperture range are forwarded to the AGP bus without need for translation. The aperture size also determines the maximum amount of system memory that can be allocated to the AGP graphics card for texture storage.

    Please note that the AGP aperture is merely address space, not actual physical memory in use. Although it is very common to hear people recommending that the AGP aperture size should be half the size of system memory, that is wrong!

    The requirement for AGP memory space shrinks as the graphics card's local memory increases in size. This is because the graphics card will have more local memory to dedicate to texture storage. So, if you upgrade to a graphics card with more memory, you shouldn't be "deceived" into thinking that you will need even more AGP memory! On the contrary, a smaller AGP memory space will be required.

    It is recommended that you keep the AGP aperture around 64MB to 128MB in size, even if your graphics card has a lot of onboard memory. This allows flexibility in the event that you actually need extra memory for texture storage. It will also keep the GART (Graphics Address Relocation Table) within a reasonable size.

    Gotta love Adrian's RP :)
    Anyway either select 128 or 256MB and bench to see whats faster - 128MB is actually faster and more stable in most cases.
  7. Mirob

    Mirob TechSpot Paladin Posts: 478

    Had to quote that, so very well said.
    Basicly the smaller the video card memory, the bigger the aperture to use.
    If you have a card with GDDR3 memory, your much better of using that any way.
  8. Merc14

    Merc14 TS Rookie Posts: 171

    Bought the book and use it a lot. Adrian Wong's "Breaking Through The BIOS Barrier" is a must have if you start messing around in BIOS. Look it up on Amazon.
  9. Arcanum

    Arcanum TS Rookie Posts: 181

    Well, the book is all good and well, but if you can't afford it, or just aren't that into that kind of things and want to be able to find explanations of almost all BIOS settings try this link:

    It's Adrian's BIOS guide, the best of it's kind, your one and only stop when you need to decipher what a BIOS setting means - I know that it helped me tremedously in the past (now I know it by heart :) LOL)

    The book is somewhat more detailed, but this guide still offers pretty good explanations + it's free.
  10. Handyman

    Handyman TS Rookie

    Basically this subject is pretty well covered by the previous posts. I'd like to add only a couple of things.
    1. You can set your AGP apeture size up to 512MB on some new motherboars eith nforce 3 or above chipsets.
    2. It doesn't have a big impact on performance. I didn't see any changes in 3DMark 2005 and AquaMark 3.
    3. Set it to 256 Mb. Should be more than enough. Do not set it to more than half of the ammount of RAM that you have.
  11. Arcanum

    Arcanum TS Rookie Posts: 181

    One thing though - 256MB can be in some configurations marginally faster than 128MB aperture (around +-1%), however it has been observed that crashes tend to get more often during games with 256MB aperture - so I'm recommending 128MB - best stability and performance.
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