Hi,
If I have an ATI All in wonder 9800 in the AGP card then a second card used
for video editing in the PCI slot next to it, can any badwidth be lost
because of the closs proximity of the AGP slot and the first PCI slot. All
the pci cards will be used up. Does it matter if instead of a video editing
card I put a modem card in there instead?
TIA,
Jeff
Page 4 of the ICH5 spec has a block diagram.
http://developer.intel.com/design/chipsets/datashts/25251601.pdf
I've left off all the I/O devices on the Southbridge, to
make the diagram a little simpler.
Processor
533M x 32bit | 6.4GB/sec (800 x 64bits)
2.1GB/sec |
AGP---------------------875P -----DDR dual channel memory
MCH -----DDR Total 6.4GB/sec
Gigabit (CSA)--------------North DDR400 x 128 bits
Ethernet 266MB/s |
|266MB/sec
|
ICH5(R) 132MB/sec (33MHz x 32 bits)
South--+---+---+---+---+---+---+
P P P P P V P
C C C C C T D
I I I I I 6 C
1 2 3 4 5 3 2
0 0
7 3
7
8
As you can see, the PCI bus is a good distance from the AGP,
and unlikely to affect it in any significant way. You are
comparing 132MB/sec theoretical (about 100MB/sec practical)
to the much higher rate of the AGP bus. Some of the AGP bus
transactions happen at 66MHz x 4 bytes = 264MB/sec, but
you won't notice any PCI going on in the background, unless
the PCI card needs a lot of processor attention to make it
work. IOW, if the PCI is not a bus master, it'll be a pig,
but as every decent card now manufactured is a bus master,
that isn't likely to happen. The only pig left, is running
an IDE disk drive in PIO mode, which is good for 3MB/sec,
and nobody does that on purpose
Short answer - nothing to worry about.
If you do see any real time effects, it could be due to
interrupt sharing, and that can be an issue for a sound card.
Just install the cards and test to see whether all the
hardware's real time requirements are being met. It is better
to just assume everything works, and then deal with issues
as they arise.
For example, some RAID cards have poor driver design, and
if you use them as a capture target for video, you'll drop
frames, whereas if you were to place even a single disk on
the Southbridge and use that, it could be trouble free. You
cannot account for driver issues with a hardware diagram
like the one above. Only real testing experience with your
system will uncover issues like that.
HTH,
Paul
