[KLUG Members] Re: Hardware Question -- 3dfx cards don't use the IRQ

[Bryan J. Smith]

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On Fri, 2002-12-27 at 14:13, Adam Bultman wrote:
> OK.  Perhaps this should go to the 'hardware' list, but inasmuch as I'm
> not subscribed...

Moving to HARDWARE, making sure I send directly to you as well.

> I have a system.  It's an Athlon Based system with a Gigabyt eMotherboard=
.

Gigabyte Model #?  BIOS Vendor (just brand name suffices)?

> I want to swap out my Voodoo3 for a GeForce2 MX card.  However, when I pu=
t
> in the GeForce2 card, my SCSI is gone.  Not that it doesn't work, it just
> never initializes.  I don't know why.  It shows that the SCSI card is
> using IRQ 15,

That's bad ... BAD!  Don't _ever_ use IRQ 14/15 -- _even_ if you disable
the second ATA channel (170h/IRQ15 normally).

First off, _all_ 3dfx cards don't use the IRQ, even in an AGP slot.  So
check to make sure you have now assigned an IRQ to AGP/VGA for the
nVidia.

Secondly, in all likelihood, you do have an IRQ assigned to the AGP/VGA
slot, and now the nVidia card is using it.  So the SCSI got "bumped" to
another IRQ for conflict avoidance.

> and that the Video is using IRQ 9 or 10.  this is  aproblem.
> The voodoo3 doesn't support 32 bit color

Er, that's a nVidia marketing strategy that fooled a lot of people.  The
fact of the matter is that the Voodoo3 had _better_ image quality than
the nVidia TNT series for 16-bit color gaming.  And it really didn't
look much worse than 32-bit color, as many sites showed.

You see, the Voodoo3 supports 22-bit dithered color in 16-bit color
mode.  This gives you faster speed than 32-bit color, but doesn't look
much worse than 32-bit color (and far better than 16-bit color).  For
16-bit color-only games, the Voodoo3 is one of the best looking chips.

But it's aged now since most titles now offer 32-bit color modes.

Furthermore nVidia, who now owns 3dfx, now supports their 22-bit
dithered color algorithm for 16-bit color titles in the GeForce4 series
(both MX and Ti products).  A little known fact, but still significant,
and makes a big difference on those older titles IMHO.

> , and, it has 1/4 the video RAM as the geforce.

Of course.  Which can limit textures.  And Glide is not as popular as it
was back when the Voodoo3 was released.

> Hence, my wanting to rid myself of it.
> I'm not certain that I can 'change the IRQ' of the video card or the SCSI
> card, aren't those just plug n' play?

Changing PCI slots often helps.

> I can't change the SCSI card's IRQ in it's BIOS. I've tried moving my
> PCI cards around to see if it would change the IRQ somehow (it's
> worked in other situations) but still no dice.

You need to change the PCI slot _and_ "reset configuration data" (Award
BIOS, or similar for others).

> Ideas?  Can I somehow allocate IRQs myself, even though it's dangerous?  =
I
> imagine a motherboard model number would help,b ut inasmuch as I don't
> have the system handy...
> Any help would be appreciated.  That voodoo3 is a serious pain in my side=
,
> because movies don't play as well as they could.

???  nVidia card didn't add motion compensation until the GeForce4.

--=20
Bryan J. Smith, E.I. (BSECE)       Contact Info:  http://thebs.org
[ http://thebs.org/files/resume/BryanJonSmith_certifications.pdf ]
------------------------------------------------------------------
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