8x AGP on non-8x mobo - Microsoft Windows

This is a discussion on 8x AGP on non-8x mobo - Microsoft Windows ; Does an 8x AGP vid card run happily on a mobo that doesnt support 8x? thanks, NT...

+ Reply to Thread
Results 1 to 8 of 8

Thread: 8x AGP on non-8x mobo

  1. 8x AGP on non-8x mobo

    Does an 8x AGP vid card run happily on a mobo that doesnt support 8x?

    thanks, NT


  2. Re: 8x AGP on non-8x mobo

    On 29 Mar 2005 16:59:31 -0800, bigcat@meeow.co.uk wrote:

    >Does an 8x AGP vid card run happily on a mobo that doesnt support 8x?


    According to the AGP spec, the speeds are backwards compatible, but
    this isn't really any assurance that it will work. Supposedly a 4x can
    run at 2x or 1x, but in practice things aren't so simple. You might
    get it to work, but happily? The 3D accelerated features that require
    the faster transfer speeds may not run well, if it all.

    More importantly, though, is the voltage difference; 8x AGP cards use
    ..8volts, other versions of AGP use 3.3 or 1.5v. 8xAGP cards can
    tolerate 1.5V (Nominally you won't DAMAGE the 8x card, but it may
    poorly or not run at all). They don't like 3.3V. Fortunately, the
    slots are keyed in a way that you can't insert a card into a slot with
    incompatible voltage. Just to make things even more complicated, some
    AGP slots support both 1.5 and .8V.

    So in other words, the answer is a definitive "maybe", but personally
    I wouldn't try it unless I was really sure. It's generally easier just
    to buy a dog-slow mid-90s vid-card for a couple bucks rather than risk
    an expensive and modern GPU.









  3. Re: 8x AGP on non-8x mobo

    Spalls Hurgenson wrote:
    > On 29 Mar 2005 16:59:31 -0800, bigcat@meeow.co.uk wrote:
    >
    > >Does an 8x AGP vid card run happily on a mobo that doesnt support

    8x?
    >
    > According to the AGP spec, the speeds are backwards compatible, but
    > this isn't really any assurance that it will work. Supposedly a 4x

    can
    > run at 2x or 1x, but in practice things aren't so simple. You might
    > get it to work, but happily? The 3D accelerated features that require
    > the faster transfer speeds may not run well, if it all.
    >
    > More importantly, though, is the voltage difference; 8x AGP cards use
    > .8volts, other versions of AGP use 3.3 or 1.5v. 8xAGP cards can
    > tolerate 1.5V (Nominally you won't DAMAGE the 8x card, but it may
    > poorly or not run at all). They don't like 3.3V. Fortunately, the
    > slots are keyed in a way that you can't insert a card into a slot

    with
    > incompatible voltage. Just to make things even more complicated, some
    > AGP slots support both 1.5 and .8V.
    >
    > So in other words, the answer is a definitive "maybe", but personally
    > I wouldn't try it unless I was really sure. It's generally easier

    just
    > to buy a dog-slow mid-90s vid-card for a couple bucks rather than

    risk
    > an expensive and modern GPU.



    thanks, good explanation. I've got a 1.3 yr old mobo that does 4x AGP,
    but currently has PCI vid fitted. I think I'll try a new 8x card to
    bing it upto a decent speed. It seems unnecessary to buy another
    machine when 100 of upgrades will get it to do everything I want.


    thanks, NT


  4. Re: 8x AGP on non-8x mobo

    bigcat@meeow.co.uk wrote:
    > Spalls Hurgenson wrote:
    > > On 29 Mar 2005 16:59:31 -0800, bigcat@meeow.co.uk wrote:


    > > >Does an 8x AGP vid card run happily on a mobo that doesnt support

    > 8x?


    Now I'm getting cornfused. At
    http://www.techsupportforum.com/arch...hp/t-1002.html
    it says:

    |AGP 1 supports 1x and 2x adapter cards with a signal level of 3.3
    volts.
    |AGP 2 supports 4x adapter cards with a signal level of 1.5 volts (it
    also supports 1x and 2x at the lower voltage, but why bother).
    |AGP 3 is a new standard that will support 8x adapter cards with a
    signal level of 0.8 volts


    The mobo manual says:
    Slots AGP 1, AGP 4X/2X universal

    So I guess it does AGP1 and AGP2, ie 3.3v and 1.5v. In which case the
    8x card should work, at 4x speed, on 1.5v IIUC. If it does, that should
    be a big improvement on pci.

    NT


  5. Re: 8x AGP on non-8x mobo


    The video processor on an 8x card will work at 8x speed in a universal slot. The main thing that will be slower is system memory access by the AGP processor, which will probably not be necessary given the amount of video memory on current AGP cards.

    bigcat@meeow.co.uk wrote:
    >
    > So I guess it does AGP1 and AGP2, ie 3.3v and 1.5v. In which case the
    > 8x card should work, at 4x speed, on 1.5v IIUC. If it does, that should
    > be a big improvement on pci.


    --
    Mike Walsh
    West Palm Beach, Florida, U.S.A.

  6. Re: 8x AGP on non-8x mobo

    > So in other words, the answer is a definitive "maybe", but personally
    > I wouldn't try it unless I was really sure. It's generally easier just
    > to buy a dog-slow mid-90s vid-card for a couple bucks rather than risk
    > an expensive and modern GPU.


    A few weeks ago we cramed a AGP 8x card (nVidia Quadro 4 980 XGL) into
    one of our heavier machines (Compaq Evo W8000) and today we did it again
    with the same 2 components and had no problems whatsoever, so I don't
    think you need to mind those things, this should work fine...

    Wimmy

  7. Re: 8x AGP on non-8x mobo

    Wim Cossement wrote:

    >> So in other words, the answer is a definitive "maybe", but personally
    >> I wouldn't try it unless I was really sure. It's generally easier just
    >> to buy a dog-slow mid-90s vid-card for a couple bucks rather than risk
    >> an expensive and modern GPU.

    >
    >
    > A few weeks ago we cramed a AGP 8x card (nVidia Quadro 4 980 XGL) into
    > one of our heavier machines (Compaq Evo W8000) and today we did it again
    > with the same 2 components and had no problems whatsoever, so I don't
    > think you need to mind those things, this should work fine...
    >
    > Wimmy


    PS: The mobo should be a AGP 4x, maybe I needed to say this :-)

  8. Re: 8x AGP on non-8x mobo

    Looks like I've got an absolute answer: both mobo and card support 4x
    AGP2 at 1.5v, so I'm buying.

    Thanks everyone!

    NT


+ Reply to Thread