Roland Scheidegger wrote:
Rob Stow wrote:

A standard 32 bit/33 MHz PCI bus compares well with AGP 1x.
It has more than enough bandwidth for 2D work and is good
enough for 3D games if you are playing at a low res like
640x480 or 800x600.

The amount of data transfered to the graphic card in 3d games is
completely independant of the resolution, since typically games do not
scale geometry details (which would make the amount of data transfered
different), thus this statement is completely false.

Do a simple test: put a Radeon 9200 in a PCI slot. Run some
gaming benchmarks. Repeat the benchmarks with an AGP version
of that card in that same machine: same GPU running at the
same clock, same type and amount of RAM at the same speed.
Note that the benchmarks are very nearly identical at low resolutions,
but the AGP card edges ahead at higher resolutions.


The reason PCI graphics cards are too slow at higher resolutions has
nothing to do with the pci bus itself, but simply because only
lowest-end graphic chips are available compared to AGP card

You missed in my previous post that my original AGP vs PCI
comparison was for a Radeon 9200 - same GPU, same amount of
RAM on the card. How then do you explain that the PCI version
of the card keeps up with the AGP version until higher
resolutions are reached ?

(high-end
graphic chips would definitely be limited by the pci bus in newer games,
but you could easily crank up resolution as much as you'd wanted without
loosing performance if such pci cards would exist).

Try out a Quadro 400 NVS. For best results you apparently
need to use it in a 64 bit/66 MHz slot instead of just a
32 bit/33 MHz slot. I saw someone demo one of those in
Calgary last fall. He did a few CAD/rendering demonstrations
and it seemed pretty impressive to me.




Roland