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Firewire / PCIe transfer rate question

  • Firewire
  • Dell
  • Components
Last response: in Components
April 5, 2009 6:56:26 AM


Trying to squeeze some more life out of my Dell before i start purchasing my components to make my own. Here is my current computer

- Dell e510
- MB: Dell Inc 0HJ054
- CPU Intel Pentium D 820 @ 2.80GHz, Bus @ 200 MHz and FSB @ 800 MHz
- 1GB RAM DDR2 266 MHz (PC2-4300) Chipset is Samsung.
- Ship date 4/4/2006

The concern is that it has two PCIe slots. One my video card is taking up (PCIe x 16) and one that is open (x1). My issue is that I don't have firewire builtin so I was going to get a SIIG PCIe firewire card that can provide 1394b to fit in there but I was reading up on the PCIe and since my box was shipped in 2006, pretty positive I have PCIe 1.0 or 1.1 which has a transfer rate of 250 MB/s[1] (big B).

The device I want to hook-up to uses firewire 800 which means transfer rates of 800 Mb/s[2] (small b). Not sure if the sources got the big B and small b mixed up but is this something I need to worry about or is PCIe (even 1.x) going to go faster than firewire 800?

Also was going to add 1 more GB of RAM. Since most motherboards don't even seem to support 1394b yet, I figure there is no waste of money on a 1394b card. DDR2 seems to still be around as well or is getting more of the same there going to be a waste? I was going to get the Gigabyte GA-EP45-UD3R to start with on my new system. I usually try to stay one major technology step behind to save on money (so no i7 or AM3 for me right now)

Thanks for any help,

- Mike

More about : firewire pcie transfer rate question

April 5, 2009 8:16:30 AM

PCI-E is immensely faster than firewire. It will not bottleneck at all. PCIE 1.1 is 250 MB/sec (which is 2Gbit/sec) per lane. A single lane (x1) card will transfer 2GBit per second, or 2.5x the maximum Firewire800 rate, and it supports cards with up to 16 data lanes (that's what a graphics card uses, PCI-E x16, or 16 lanes at 2000Mb/sec per lane). You will have no trouble whatsoever with transfer rates.
April 5, 2009 8:28:43 AM

And more RAM will help A LOT (go to 3 or 4GB total, whichever is cheaper).
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April 5, 2009 3:50:12 PM

Great, thanks for the help - I might be able to stretch this system out until the i7 prices come down.

Thanks again,

- Mike
April 5, 2009 5:07:46 PM

Now is PCI 2.x faster than firewire 800? I only have 1 expansion slot for PCIe so would like to save it for another thing I have my eye on if possible.

I see PCI 2.x has a peak transfer rate of 533MB/s if it is running 66Mhz - which will give me 4,264 Mbps, where according to reference [2] in OP, firewire 800 does 3200 Mbps. However in the same article, it states (for 1394b) - "This specification and corresponding products allow a transfer rate of 786.432 Mbit/s full-duplex via a new encoding scheme termed beta mode."

So confusion ensues unless it should read "786.432 MB/s" but not sure. I guess the short question is, is firewire 1394b capable of going faster than a PCI 2.x ?

Thanks again all!

- Mike

April 5, 2009 6:11:04 PM

I would say you are probably fine with a PCI port. Honestly, very few devices are capable of 700 megabyte per second transfers anyways, so the connection is not likely to be your bottleneck. I'd say a PCI card would perform just fine.
April 5, 2009 6:50:49 PM

April 6, 2009 6:18:53 AM

The peak transfer rate for firewire 800 is 800 megabits per second (100 MB/s) and the control overhead usually shaves a little off of that. A Firewire 800 RAID could reach that data rate pretty quickly. But keep in mind, that PCI (not PCI-E) is a shared bus so anything else in the system on that PCI bus subtracts from the PCI data rate.
April 6, 2009 5:23:03 PM

Any device that could bottleneck firewire 800 would likely cost much more than a new high-end pc. I doubt you will experience any throughput problems with 1394b pci-e adapter in your computer.
April 6, 2009 10:45:31 PM

Thanks, This will be the only PCI device in the system. Also the device I'm hooking up is an RME Fireface 800 audio recording device which new runs around US$1,600. It has Firewire 400 on it so I'm guessing the device could not exceed firewire 400 speeds else there would be some problems.

Thanks for all the replies.

- Mike
April 6, 2009 11:06:41 PM

naah, it takes alot of firewire 400 audio channels to top that out... hence why there are so many USB 2 interfaces, and quite a few that are usb 1