Video cards : need advise on USED cards...

Vincent Trouilliez vincent.trouilliez at
Fri Jun 3 02:03:46 UTC 2005

> Hi everyone... About the above: Sorry to say this, but that's not true!
> ***Be warned***!!!  You must have a VGA adapter with an AGP *version*
> that's compatible with (or supported by) your mainboard.
> Don't confuse AGP “version” with AGP “speed” or “rate”.
> >From a mainboard point of view:
>       * AGP v1.0 support speed rates of 1x only or 1x and 2x and operate
>         at 3.3 Volts.  Those found on very old Pentium 2, K6, and Cyrix
>         systems.
>       * AGP v2.0 support speed rates of 1x, 2x, and 4x and run at 2.5
>         Volts.  You'll found those in Pentium 3, early Athlons, and
>         VIA's C3 systems.
>       * AGP v3.0 support speed rates of 1x, 2x, 4x, and 8x and run at
>         1.8 Volts (I think, I'm not 100% sure).  You'll find this on
>         newer systems.  Most _new_ AGP cards are *only* AGP v3.0, so be
>         careful.
> Depending on your mainboard specifications, it may support, say, AGP
> v1.0 and v2.0.  This specific mainboard will not accept an AGP adapter
> that's AGP v3.0.  Likewise, some AGP VGA adapter support more than one
> version of AGP specification.  I have been beaten a lot by this
> confusion in the past thinking “I'll just lower my mainboard's AGP rate
> from the BIOS and this AGP card will work like a charm”.  Needless to
> say, I was wrong.
> Ziyad

Hi Ziyad,

Thanks for the technical info, much welcomed.
I checked my motherboard's user manual, it says, I quote :

- Supports AGP v2.0 2x/4x (1.5V only)

So it's strange. Although it says v2.0, it also says that in x4 mode, it
needs 1.5v, which looks from your description like v3.0 ?
So there is a ray of hope that my AGP slot is compatible with v3.0
(hence modern) x4 cards ?
Obviously the ultimate test is to stuff such a board in there and see
what happens, but sadly I can't afford to buy a dozen cards, even cheap
and used, to fry them one after the other until I find one that
works ! ;o)

This is all getting a bit of a nightmare. Lots of trouble to identify a
card that maybe will, or maybe won't, work on my obsolete motherboard...
probably for not much improvement.
Hmmm, I guess it's wisest to give up and wait a couple years, when I
change the motherboard, hence can just get any card out there and plug
it in without much thinking...
Well, at least I tried. Thanks guys for all the technical info....


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