[AG-TECH] AGP slots on Display machine

Justin Binns binns at mcs.anl.gov
Wed Nov 13 08:42:25 CST 2002

The short answer: yes - you get a *big* performance win with (2).

The longer answer:

Assuming your processor and memory capabilities are sufficient, the first
bottleneck you run into in decoding and displaying video streams is the
ability to get pixel data to the frame buffer.  In the (1) case below, you
have a single 32/33 (32-bit/33Mhz) PCI slot over which you are trying to
drive all the pixels.  This is going to be slow.  In the case (2) below,
you have two slots, and one of them is AGP (with a G450, that's AGP 4X,
which comes up to 8x more speed than the PCI slot above), and the other,
still a 32/33 PCI slot, but only driving one screen of decoded pixels (you
usually aren't displaying a lot of streams on the operator console).

This speed difference will be less if you are using a non-optimized Vic,
but if you're running Win2k or WinXP and have the latest display software,
you'll be using the direct-draw enabled Vic, with which you should notice
an obvious and significant performance difference.

Justin Binns

On Wed, 13 Nov 2002, Philip J McCormick wrote:

> Would there be a huge difference (i.e. performance / picture quality)
> between:
> 1) running 3 projectors and the display console from a Matrox G200 Quad PCI
> card (i.e. on a machine that doesn't have an AGP slot)
> 2) running 2 projectors from a Matrox Millenium G450 32Mb Dual Head AGP
> card, 1 projector and display console from a Matrox Dual PCI card?
> Thanks
> Phil McCormick

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