Is a PCI-E 1394a card better for DAW than my current standard PCI card? (MR816 CSX)

[blueguitarbob]

The peak transfer rate of 32-bit, standard PCI is 133MB/sec. That is greater than the peak transfer rate of Firewire 800, or 1394b, which is just under 100MB/sec. (1394b is just under 800 Mbits/second, or roughly just under 100 MBYTES/sec).

So a standard PCI connection is fast enough for both Firewire 400 and 800.

However, in the architecture of a modern PC, all the PCI slots combine to use a single PCIe connection to the southbridge. If you have other PCI slots filled, your Firewire card will be competing for that bandwidth to the southbridge. If you are like me, and the Firewire card is the only PCI slot filled, then it is fine... but if you have lots of other PCI cards installed, then you might hit a total bandwidth limit. You'll have to make that determination for yourself.

Should you replace your PCI Firewire 400 card? Maybe. You might be able to replace it with a newer PCI card and see some increase in speed, just because there have been advances in the chipsets and drivers. I recommend Unibrain products:

Welcome to Unibrain web site - The Firewire (Firewire 800 - IEEE 1394b) Innovators

Their newest PCI and PCIe cards are very good:

FireBoard 800-e™ 1394b (Firewire-800) OHCI PCI Express adapter

FireBoard-800™ V.2 1394b (Firewire-800) OHCI PCI adapter


Both of these cards can maintain 400Mb and 800Mb speeds, although the PCIe card can do 8 isochronous connections vs 4 for the PCI card. That's only a limiting factor if you have more than 4 devices connected simultaneously.

Also, you don't need a card with both 1394a and 1394b connections. 1394b (800) is down-compatible with 1394a (400). You just need to get a converter cable.

[deniroh]

thanks for the info. The only other card in a PCI slot is my VSL-2020 audio interface, which is getting pulled out when I install my new MR816CSX, so I think I'll stick with what I got until I upgrade my whole computer to the i7 core platform next year.

cheers!

[blueguitarbob]

Actually, I want to correct myself:

Both of these cards can maintain 400Mb and 800Mb speeds, although the PCIe card can do 8 isochronous connections vs 4 for the PCI card. That's only a limiting factor if you have more than 4 devices connected simultaneously.


Hard drives don't use isochronous transfers. So that spec doesn't apply if you are only using your Firewire port for hard drive storage.

It may be an issue if you are using Firewire for video, audio streaming, or an audio DSP device (Powercore, Duende, etc). I know at least some types of video use isochronous transfers, but I don't know about the others. If that's important to you, it would be worth some research. The PCIe card's larger 8 isochronous connection limit might be a reason to buy it, over the standard PCI version.

[joris de man]

What's probably more important is that your firewire cards have the right chipset.
Via chipsets can cause clicks in the audio, and in general one of the best chipsets for audio is the Texas Instruments one.
There are both pcie and pci firewire cards that have them, afaik most belkin firewire cards use said chipset.

Cheers,

Joe