PCI cards, bus speed, and data transfer bottlenecks

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I originally posted this to comp.hardwar and did not receive a response, so I'm
trying again here.

My current assumption is that I have an available PCI Express slot (even after
the Video/Sound ones).  

Assuming I do, is it worthwhile to go all out and get a FireWire 800 ahem...
IEEE 1394 800 Mbps card?  I'm planning to
connect up probably a DV camera (someday, I can dream...), but more recently, a
Media Card reader.   I want the fastest
possible data transfer from the Compact Flash card my Canon uses.  It's not out
of the question that I will someday
spring for an external DVD writer, and I don't want the weird/slow connection to
increase the risk of buffer underruns.

I could really use a good conversion tool or some more understanding of the
conversion between MHz and MB/s.  Seems
others have asked this question, but so far there is no detail about how to
calculate this for yourself.  It looks like
the essential piece of data is how many bits/bytes are transfered across the FSB
and PCI buses per clock tick - this is
a hard stat to find.  Can someone explain?

I mean, if my FSB can't transfer data to the RAM as fast as it's coming off the
PCI Express bus, then why bother using
that slot?  I don't think that's the case, but right now, I cannot confirm it.

I'm looking for the whole picture (I've been piecing it together), step by step
from the media card to the reader, to
the external connection, to the PCI bus, to the FSB, to the RAM, to the CPU, (to
the) hard drive. I'm trying to
eliminate bandwidth bottlenecks if I can, and save money on components if I
can't.  (FYI:  My HD is SCSI @ 320 MB/s)

Also, since I have SCSI, I can look into maybe finding an external SCSI Media
Card reading device if it's faster than
available PCI bandwidth.

References to similar threads in comp.hardware (links from google, because its'
easier to search that way):



"the SD RAM transfer speed at 100mhz is 800mB/s while the 100mhz
DDR is 1.6gB/s"  -- Anthony Brohan

The last statement made me realize that there's no way to calculate MB/s from
MHz unless you know how much data moves at
each tick. But I dont' know how to find that out re: FSB and PCI.

Re: PCI cards, bus speed, and data transfer bottlenecks

On Sun, 22 May 2005 19:43:53 GMT, them_age@yahoo.com wrote:

Quoted text here. Click to load it

has nothing to do with real life transfers IMHO ...

Quoted text here. Click to load it

For Ram see my site under comp/benches -updated ... :-)

                         Regards ,  SPAJKY ®
   mail addr. @ my site @ http://www.spajky.vze.com
3rd Ann.: - "Tualatin OC-ed / BX-Slot1 / inaudible setup!"

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