New computer, do not know if it supports AGP 4/8x

By geno2k3 ยท 7 replies
Sep 13, 2007
  1. Hi, i bought a computer form someone on criagslist. I checked the CPU-z and it says maximum supported video card is 4xagp and its agp version 2.0. Will this computer be able to support a agp 4/8x card? or just agp 2/4x cards?

    Information on my motherboard (from cpuz)


    Northbridge Intel i850 rev. A2
    Southbridge Intel 82801BA (ICH2) rev. 04
    Graphic Interface AGP
    AGP Revision 2.0
    AGP Transfer Rate 4x
    AGP SBA not supported, not enabled
    Memory Type RDRAM
    Memory Size 1024 MBytes
    Memory Frequency 398.8 MHz (1:1)
    Total CAS# (tRDRAM) 10
    Row To Column (tRCD) 9
  2. Gosugod

    Gosugod TS Rookie Posts: 40

    AGP 2.0 is a 1.5V AGP slot capable of 4x,2x and 1x speeds.

    AGP 3.0 is keyed like a 1.5V AGP 2.0 slot, but it only uses 0.8V of power. It supports 8X, 4X, 2X and 1X speeds.

    Rule #1: Speeds are backwards compatible

    AGP Speeds are required to be backwards compatible. This means that an 8X video card MUST be able to run at 4x, 2x, or 1x speeds. However, this does NOT necessarily mean that your 8X card will run on a 4x slot.

    Signalling Voltage incompatibility
    Because speeds must be backwards compatible, Signalling Voltage is where incompatibilities arise. Basically:

    All 8x cards are 0.8v AGP 3.0 spec
    8x cards will fit in 1.5V slots, and can tolerate the voltage, but will NOT run properly
    4x cards can be either 1.5V or 0.8V
    2x and 1x cards are either 3.3V or 1.5V

    Except in the case of the 8X cards, using the wrong voltage card with the wrong motherboard can result in damage in card and board
    If you install a card of incompatible voltages with the motherboard's specs, the card will NOT run

    The connectors on AGP video cards are keyed in such a way that you can only install equipment that have compatible Voltage keyed connectors. Normally the key of the card determines its signal voltage. AGP 1.0 and AGP 2.0 cards using a 1.5V key will signal at 1.5 volts. However, AGP 3.0 devices can tolerate 1.5V - they won't be destroyed, they just might not work properly.

    The bottomline is that your 8X video card can theoretically be safely TESTED in any 1.5V motherboard for compatibility. But if you know for a fact that your board only runs 1.5V AGP 2.0 spec and your 8X AGP 3.0 card runs only 0.8v spec, then the two should NOT be compatible one another. At the very least it will be unstable, if it runs at all. However, we've had a lot of users tell us that their AGP 8x cards work on 4x only motherboards. This is likely due to the fact that some AGP8X video cards are in fact universal 1.5V capable AGP3.0 cards that can run on either 1.5V or 0.8V (remember, AGP speeds are backwards compatible, only voltage incompatibilies cause problems). The other possibility
  3. BlameCanada

    BlameCanada TS Rookie Posts: 320

    It will support most later cards,but will just run at 4x.

    Whatever card your thinking of getting, google for

    any issues.
  4. geno2k3

    geno2k3 TS Rookie Topic Starter Posts: 46

    Thank you for the great responses.

    I have a quick question i think you guys can help me out with.

    If you guys can provide me with a brief list of compatable video cards with my system it will get me going on what / which card to purchase. I just need an idea of what my computer can use.
  5. BlameCanada

    BlameCanada TS Rookie Posts: 320

    There is a very good guide HERE Also a long list of cards and boards.

    AGP 3 can read for AGP 4 in that list.
  6. geno2k3

    geno2k3 TS Rookie Topic Starter Posts: 46

  7. BlameCanada

    BlameCanada TS Rookie Posts: 320

    Yeah that will work.

    About 98% of new cards will work.
  8. geno2k3

    geno2k3 TS Rookie Topic Starter Posts: 46

    Thanks alot for all the replies. After doing a little bit of my own research. I found out my very first computer i used to game with was also a 4x computer. Emachiens t2200 i think and my geforce 6800 (8xagp) used to run great on it.
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