Re: newbie questions for amd64
On Mon, Nov 17, 2003 at 04:25:56PM -0500, Kyle Rose wrote:
> It's not PCI-X itself, but it's compatible with PCI-X slots: it will
> work in a 3.3V or 5V slot.
*ouch*
I remember they made some fuss about PCI-X parts a few months ago (was
it for SIGGRAPH?). I hope they mean real PCI-X and not this, because
if I understand you correctly, this is a plain old PCI device, and
that's worse than AGP 1x. And this card worked fine for DVD playback
on a dual Athlon machine? Let's see... 33 MHz @ 32 bits is 132 MB/s,
which is an order of magnitude above DVD requirements. Hmm... maybe,
as long as you have DMA...
> Well, I think in general companies downplay their PCI support because
> only us whackos with dual-head systems care.
Actually it's because of the insane upload rates (geometry, textures,
whatever) of modern games (and some of us, non-gamers), some of which
want _more_ than AGP 4x (1 GB/s).
> If I could get a reasonable AGP dual-head card with DVI-D output and
> good, reliable 2D/3D performance under Linux, I'd probably go that
> route; alas, I haven't found any. Do you know of any?
If you look at the spec, nothing really speaks against a system with
multiple AGP bridges, but it's so vertical that I don't think anyone
has bothered to produce one. Interestingly an n-way Opteron should be
able to cope with this, but the motherboards don't support that config.
From the look of it, even the kernel supports this, but I asked Dave
Jones if there was a reason for that (meaning, is it because it can be
done or because there's a box in a basement somewhere where this
actually exists) but he never came back to me. There's a company (big
name, I'm not sure if I can really mention it, sorry) which considered
putting out a system with support for multiple AGP devices, but it
never came out (and they use the wrong processor, too expensive, too
slow :-) and they put their money on a system with multiple PCI-X
bridges, which is not that vertical (since storage and network people
will surely like that). Another company, SGI, actually has a system
with multiple PCI cards which are going to turn into PCI-X at some
point in the future, AFAIUI (reading between the lines in press
releases). This is the reason why I asked if yours was PCI-X, since
this is going to be the preferred way of getting multiple GPUs on a
single machine in the future. In fact, AGP should not be there in the
first place in these systems, but the lack of PCI-X parts pushed AMD
towards this solution, at least for the moment.
> Hey, I even offered to give them root on my box. We'll see if they
> have anything to say. :)
Oh. Well, good luck then :-)
Marcelo
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