Daisychaining Firewire 400 and 800 -- Where are the speed bottlenecks?

[proflemon]

Does the order in which mixed firewire 400 and 800 devices are chained matter regarding speed?

I'm hoping to daisychain 3 firewire devices:

1) External hard drive "A", which has only FW 400 ports.
2) A Sony DV deck, which has only FW 400.
3) External hard drive "B", which has FW 400 and FW 800.

The FW 800 drive "B" would connect to the computer via FW 800.

It makes perfect sense to me that if the FW 800 was in the middle of the chain, its data would be bottlenecked in whatever direction it travels. My question though is...If the FW 800 drive is the device that is connected directly to the computer's FW 800 port, will that FW 800 drive send data at FW 800 speeds? Or is it the case that if any single FW 400 device is in the chain, that brings the whole chain down to FW 400 speeds (regardless of placement in the chain)?

Thanks (from a 1st time poster).

 

[MagicWok]

If you daisy chain through this method:

Computer -> FW800 Device -> FW400 Device -> FW400 Device


I would presume that if accessing the FW800 drive only, you would be able to get FW800 transfer speed for that one device only. You would need to try this though, as though in theory I believe it would work - the way the devices and your Mac handle daisy-chained devices could change everything...

 

[proflemon]

Thanks for the reply. How can one know (objectively) the results of different daisychaining configurations? Can OS X run a speed test?

 

[proflemon]

So I connected the FW 800 drive to the computer's FW 800 port, then daisychained the FW 400 drive to the FW 800 drive. I don't know how to properly test the speeds of both drives when configured this way, but my anecdotal experiment's results were clear...

I tried the same huge Quicktime file on both drives, then played each in Final Cut Pro. Results: the file stuttered/froze/barely played from the FW 400; plays almost perfectly from the FW 800.

 

[fivepoint]

Does the order in which mixed firewire 400 and 800 devices are chained matter regarding speed?

I'm hoping to daisychain 3 firewire devices:

1) External hard drive "A", which has only FW 400 ports.
2) A Sony DV deck, which has only FW 400.
3) External hard drive "B", which has FW 400 and FW 800.

The FW 800 drive "B" would connect to the computer via FW 800.

It makes perfect sense to me that if the FW 800 was in the middle of the chain, its data would be bottlenecked in whatever direction it travels. My question though is...If the FW 800 drive is the device that is connected directly to the computer's FW 800 port, will that FW 800 drive send data at FW 800 speeds? Or is it the case that if any single FW 400 device is in the chain, that brings the whole chain down to FW 400 speeds (regardless of placement in the chain)?

Thanks (from a 1st time poster).

I would also REALLY like to know the answer to this question. I am in the exact same boat with these devices:

a) a brand new FW800 750GB Time Machine Drive
b) a 160GB FW400 External Drive
c) a Sony Handycam FW400 docking station

If I daisychain like this:
computer > FW800 device > FW400 device > FW400 device

does my FW800 operate at full FW800 speeds, or is it taken down to FW400 speeds? Also, are there any drawbacks to this setup?

 

[chinarider]

Does the order in which mixed firewire 400 and 800 devices are chained matter regarding speed?

I'm hoping to daisychain 3 firewire devices:

1) External hard drive "A", which has only FW 400 ports.
2) A Sony DV deck, which has only FW 400.
3) External hard drive "B", which has FW 400 and FW 800.

The FW 800 drive "B" would connect to the computer via FW 800.

It makes perfect sense to me that if the FW 800 was in the middle of the chain, its data would be bottlenecked in whatever direction it travels. My question though is...If the FW 800 drive is the device that is connected directly to the computer's FW 800 port, will that FW 800 drive send data at FW 800 speeds? Or is it the case that if any single FW 400 device is in the chain, that brings the whole chain down to FW 400 speeds (regardless of placement in the chain)?

Thanks (from a 1st time poster).

You may want to post this in the DV forum. I *THINK* you will run into problems if you try to use your deck and drives at the same time (ie: Capturing video from the deck onto your HD or the other way around)

There are many devices you cannot use on the same FW Bus as your drives -I know that AJA IO and XDCam Decks can fall into this category.

Again, this is an educated guess - I am still learning myself. I have heard that if you DO run into problems, consider getting another FW card as this will help.

 

[fivepoint]

Assuming that you aren't sending data from the camcorder to the HD it is daisy chained through though... can you do it otherwise? Will the performance suffer? Does the FW800 device maintain its high performance?

 

[harddriveowner]

connect the camcorder to the computer directly

The camcorder needs to be connected directly to the Mac when uploading the data. Just plug it into the FW 400 port directly, not into an external harddrive or through a firewire hub. the safest way to get the data into the computer's harddrive without skipped frames, or crashes, is the direct connect.
I know from experience. What I don't understand is why you re using only the FW800 port. Could you explain.

 

[fivepoint]

The camcorder needs to be connected directly to the Mac when uploading the data. Just plug it into the FW 400 port directly, not into an external harddrive or through a firewire hub. the safest way to get the data into the computer's harddrive without skipped frames, or crashes, is the direct connect.
I know from experience. What I don't understand is why you re using only the FW800 port. Could you explain.

A) I've been using the camcorder daisychained through the hard drive for several months now. It works perfectly.

B) I have additional FW400 items to plug in to the computer, and I would like them all plugged in at the same time. I am wondering if it is possible to daisychain FW400 devcices off of FW800 devices. That's all.

 

[Richard Flynn]

In principle, you can see how fast OS X is communicating with FireWire devices in System Profiler. Open System Profiler (Applications > Utilities > System Profiler), and select 'FireWire' on the left. All your FireWire devices will then be listed on the right; clicking on each one you can see the "Maximum Speed" and the "Connection Speed". The key information here is "Connection Speed". The "Maximum Speed" will display whatever the theoretical maximum is for that device. At the moment I have a FW800-capable drive connected to a FW400 port, and this is how that's reported:

 Maximum Speed:	Up to 800 Mb/sec
 Connection Speed:	Up to 400 Mb/sec

Like the others, I'd be interested to hear your reports (although I'm now going to try stringing a FW400 device from a FW800 device to see what happens for me).

 

[proflemon]

I never had the configuration I mentioned above assembled again, so I couldn't do any official test--but it's clear on my system that a giant QuickTime file plays fine from a FW 800 drive connected directly to FW 800 port, even while having FW 400 devices connected to the in-use FW 800 drive...but the same file would barely play from a FW 400 drive daisychained through the same FW 800 drive.

Someone mentioned above that having your DV deck going straight to a computer port minimizes dropped frames etc. I never experienced dropped frames when I was daisychaining the deck, but I read many opinions saying that dropped frames are more likely when daisychaining...I read enough to switch my deck to connect directly to the computer.

If it's of any use to anyone, I currently have 2 FW 800 drives daisychained together, going to FW 800 port. DV deck going straight to FW 400 port. Working fine.

 

[BalixtraP]

In principle, you can see how fast OS X is communicating with FireWire devices in System Profiler. Open System Profiler (Applications > Utilities > System Profiler), and select 'FireWire' on the left. All your FireWire devices will then be listed on the right; clicking on each one you can see the "Maximum Speed" and the "Connection Speed". The key information here is "Connection Speed". The "Maximum Speed" will display whatever the theoretical maximum is for that device. At the moment I have a FW800-capable drive connected to a FW400 port, and this is how that's reported:

 Maximum Speed:    Up to 800 Mb/sec
 Connection Speed: Up to 400 Mb/sec

Like the others, I'd be interested to hear your reports (although I'm now going to try stringing a FW400 device from a FW800 device to see what happens for me).

I am posting 2 years after this thread because this is a top result in Google searching on this topic, and I had the same question about mixing FW400 and FW800 devices, and I have an answer to the above.

Placing a FW400 audio interface first and chaining a OWC FW800 hard drive enclosure off of that, one gets:

 Maximum Speed:    Up to 400 Mb/sec
 Connection Speed: Up to 400 Mb/sec

for the audio interface, and:

 Maximum Speed:    Up to 800 Mb/sec
 Connection Speed: Up to 400 Mb/sec

for the hard drive.

Doing it in the opposite order, with the FW800 hard drive connected to the Mac first, and the FW400 audio daisy chained off of the hard drive, yields the same results for the audio interface, but for the hard drive, the system profiler gives:

 Maximum Speed:    Up to 800 Mb/sec
 Connection Speed: Up to 800 Mb/sec

I get this result even when the FW400 audio interface is selected and streaming audio.

So these results seem to show that connecting the FW800 device first to the computer allows for FW800 connection speed even when a FW400 device is chained off of the FW800 and being routed through it.

It is possible this all depends on the specific FW800 controller in the drive. And I haven't yet actually benchmarked the drive while doing audio at the same time.