Question on Daisy Chaining FW 400 drive to a FW 800 drive

[powerbook911]

I may soon buy one of the newer generation iMacs that drop the FW400, includes 800 only.

On my current Mac, I have a FW800 drive and a FW 400 drive. I use the 400 for time machine as speed is less important. My current iMac has a 400 & 800 connector.

I have tested connecting the 400 to the 800 drive via daisy chaining, so everything is pulling off the 800 connector, so this assures me I can do this with the new iMac.

However.......

Does it slow down your 800 drive when it has a 400 chained off of it? Or, if the 800 is the first drive connected to your iMac, do you maintain full speed?

Thanks for the help.

 

[pastrychef]

Does it slow down your 800 drive when it has a 400 chained off of it?

Yes.

 

[powerbook911]

Thats a bummer. I guess another negative of Apple putting only FW800 on the new macs.

 

[powerbook911]

Hate to ask another question, but I was wondering...

If the FW 400 drive on the other side of the 800 isn't being actively used at a given point of time, does the 800 operate near it's full speed ?

I have done some tests of transferring files between the drives. The 800 drive copies things to other drives faster than the 400, even when the 400 is attached. Furthermore, the timings I have done of the 800 drive seem to be spot on identical no matter if it has the 400 on the other side of it daisy chained, or not.

Perhaps, except when the 400 is really actively doing something, it doesn't slow the 800 down much? After all, the pipe between the 800 and Imac is still the FW 800 interface.

 

[pastrychef]

I don't know the answer to this one...

 

[DoFoT9]

i would say no to the 2nd question. its like having different RAM speeds. if you have a 800MHz stick and a 1066MHz stick, it will always run at 800MHz even if you are not using the whole stick (bad analogy i know).