Firewire bus question Mac pro

[cane creek]

On the Mac pro 8 core 2.8 do the 2 firewire 400 ports both share the same bus ?

im interested in knowing as i own a TC powecore firewire and im interested in buying a M-audio profire 2626 soundcard , if their both sharing the same bus i may run into bandwidth problems if im maxing out the powercore and running lots of things on the m-audio.
However if they are not sharing the same bus ill have no problems.

 

[trainguy77]

http://developer.apple.com/document...h_FireWire/Articles/FireW_implementation.html

So yes they are on the same bus. However, i think the bus speed would be greater then that of a single port.

 

[cane creek]

Thanks for the reply

Blimey all four share the same bus , i thought this was a "PRO" product lol

so thats a waste of time looking at the RME fireface 800 as an alternative as it would be on the same bus anyway.

 

[trainguy77]

Thanks for the reply

Blimey all four share the same bus , i thought this was a "PRO" product lol

so thats a waste of time looking at the RME fireface 800 as an alternative as it would be on the same bus anyway.

Well, the bus could be faster then any single port i am not sure. The other option is buy a PCI Express firewire card so its on a different bus. But try it on the internal one first.

 

[cane creek]

Well, the bus could be faster then any single port i am not sure. The other option is buy a PCI Express firewire card so its on a different bus. But try it on the internal one first.

I would get a PCIe firewire card but PCIe slots are like gold dust , ive only got 3 and 2 are taken up by a UAD-1 / UAD-2 and i have my eye on SSl Duende PCIe for the 3rd slot lol

 

[trainguy77]

Well are both the devices you want firewire 400 devices? If so the bus for sure supports 800 speeds which would mean two 400 devices won't max out the bus.

Also will you be using the two devices at the same time?

 

[cane creek]

Well are both the devices you want firewire 400 devices? If so the bus for sure supports 800 speeds which would mean two 400 devices won't max out the bus.

Also will you be using the two devices at the same time?

Yes both FW 400 Yes that does make sence what your saying and yes i would be using both at the sametime

 

[cube]

When you plug in a FW400 device in a FW800 bus the whole thing drops down to 400 speed.

 

[trainguy77]

Yes both FW 400 Yes that does make sence what your saying and yes i would be using both at the sametime

Thats my theory at least.

When you plug in a FW400 device in a FW800 bus the whole thing drops down to 400 speed.

Yes but he will be plugging two 400 devices into separate ports. He is worried about the actual bus transfer speed. And the bus is the same for all 4 firewire ports.