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I have read up on this and sadly, have gotten some contradicting information.

My issue is, my firewire units 'complained' when plugged into a PCI interface and requested they go direct into the board (and I'm really sorry I can't remember the exact error message as my PC is currently in pieces).

So, I can only assume this is the case because PCI is not fast enough / powerful enough.

Plugging direct into the IEEE header fixed the issue but my new motherboard doesn't have any IEEE headers (an oversight on my part!).

So is firewire to PCI vs PCI-E going to yield much difference in results. I have seen stats which show:

Firewire 800 - 800 megabits - 100MB/s
Firewire 400 - 400 megabits - 50MB/s

PCI - 133MB/s
PCI-E x1 - 250MB/s
PCI-E x16 - 4,000MB/s 

But on the same forum they can be quoted "Pretty much the fastest protocol can't saturate a PCI's bandwidth, so you don't really need to go to PCI-E." This worries me as I've just spent a lot on a motherboard and need to get the firewire working.

I will be plugging in 2 Firewire devices into the firewire interface (this is for music recording and I assume quality is key as there is a lot of data transfer).

Anyway, my question is, is there any difference in speed between a firewire plugged into PCI, PCI-E and PCI-X for both firewire 400 and firewire 800?

Thank you

Dave

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I can't think of any motherboard that would have both PCI-E and PCI-X but i see from the question the rather unloved, server centric pci-x isn't one of the interfaces you could use. The exact error would help hugely here since it'll help narrow down if its a power issue (maybe not enough power for the unit) or some other thing. –  Journeyman Geek Jul 30 '12 at 9:21
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2 Answers 2

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WHAT?! Firewire is an IEEE STANDARD. It's not a "port."

FYI:The Institute of Electrical and Electronics Engineers (IEEE) is a non-profit professional association headquartered in New York City that is dedicated to advancing technological innovation and excellence. You can maybe think of the IEEE as something like the Underwriters Laboratory (UL) which is another group dedicated to making sure things are safe for consumers (and will work to a certain degree of claim by the manufacturer(s).

Therefore, it doens't matter how you provide firewire ports to your computer since you can do it many different ways. Most common would be with with an embedded controller (embedded to your motherboard) or via an add-on card that plugs into a PCI slot or something. As long as these firewire ports adhere to the IEEE 1394 "standard" you're good to go. That's about as simple as I can make it cause when you say you provide a IEEE "port" I just have to be asking, WTF?!

So, I guess the answer would be no. It makes no difference what port you plug a Firewire device into so long as the port itself adheres to the "firewire" standard. You may still have some choke points like an overburdened controller or something (which is why it's pretty critical to have correct drivers installed), but the firewire ports won't likely be the cause of any poor performance.

Personally, I'd be looking at USB3 if I were in need of a cheap, fast, and widely accepted port. Otherwise, you may want to be looking at eSATA or external SCSI.

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Thank you for your answer - sadly, I can't recreate the issue as the board died and the devices are Firewire only (so no option of USB 3) –  Dave Rook Jul 30 '12 at 9:46
    
Actually, a follow up question but relevant to this thread - If we feel that PCI or PCI-E should make no (limited) difference then why do they exist (with such varied prices)? –  Dave Rook Jul 30 '12 at 11:21
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A few corrections and additions:

1)

Firewire 800 - 800 megabits - 100MB/s  (Or... 80MB/sec)
Firewire 400 - 400 megabits -  50MB/s

That is correct is you want the theoretical maximum speed and you ignore protocol overhead. Dividing by 10 rather than by 8 is probably more realistic.

2)

PCI - 133MB/s

  • PCI is a bus. This means this bandwidth is share by all devices on the bus.
    Thus if you plug in 4 firewire devices on a single PCI bus and try to use them at the same time then they each can use about ¼th of the bandwidth.
  • PCI can be 32 bit wide and running at 33Mhz, resulting in the specified 133MB/s. (And it usually is 32/33 in cheap PC motherboards). But you also have 64 bit wide and 66Mhz PCI busses.

3)

PCI-E x1  -   250MB/s
PCI-E x16 - 4,000MB/s 

This is a bit lacking.

PCIe version one is 2.5Gbit per lane. A device connected via a single lane (PCIe x1) can move up to 2.5Gbit/second. Just like PCI it has overhead.

PCIe supports x1, x4, x8 and x16. You can put a device into a larger slot and get the lowest common dominiator. (e.g. if you put a x1 device in a x4 slot you will get a single link connection allowing up to 2.5Gb

Then there is PCIe version 2. If both devices support it you can move 5Gbit/sec per lane.

PCIe version 3 is relative new. It has even higher speeds and more efficient signal encoding. The result of this is yet another speed doubling.

Summarised:

                        x1     x4     x8    x16
          PCIe v1      2.5     10     20    40        in Gigabit per second
          PCIe v2        5     20     40    80
          PCIe v3       10     40     80   160


Any firewire card should work in both PCI and PCIe slots. However if you plug a firewire-800 card into a PCI slot then you will probably not reach maximum speed. But it should still work.

If you want to avoid speed bottlenecks due to the system bus, use PCIe.

If you want to avoid speed bottlenecks due to the system bus and have

If you use four IE1394-800 ports at the same time and you want to avoid speed bottlenecks due to the system bus, then consider a card with a better interface than PCIe (v1) x1 or use multiple cards. (PCIe is point to point, not a bus. One card will not slow down another card).

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Thank you for taking the time (although it will take me a few reads to digest). Beer on me for this , thank you –  Dave Rook Jul 30 '12 at 19:52
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