> > What bus interface is the card going to have? PCI is hopelessly slow
> > for graphics.
>
> It depends on what you are sending over the bus. AGP was designed to
> rapidly access system memory so that it could be used for graphics
> memory. Having a lot of memory on the video board tends to negate this
> need. We could use 64 bit @ 66 MHz.
Very few machines that the OGC would go into have PCI-X. So you only
get "plain" PCI. And you have to share that 133 MBps with the other
PCI devices. And lots of machines have other important high-bandwidth
devices on the PCI bus.
That's fine for mostly static things like most desktop apps. Email,
spreadsheet, image viewer, most web browser use, ...
But many (most?) users are going to want to be able to watch video.
OGC is supposed to support 2 dual-link displays. Last I read,
OGC is not going to have an mpeg decoder, and even the hw scaler has
been dropped. Even if the CPU is fast enough (most will not be), and
even if you give 100% of the PCI bus to the OGC (not realistic), and
only driving 1 display, the bits just don't fit.
What to do?
a) Don't support video (lost sales to anyone who wants/needs video)
b) Switch to PCI-e (lost sales to PCI-only and PCI&AGP systems,
still need a very fast CPU)
c) Include a mpeg decoder and hw scaler (chip is more complex
to design, larger and more expensive)
d) Include a separate decoder chip. (If there is one that is
documented, and is usable with the architecture.)
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