two hard drives on one firewire port??

Discussion in 'iMac' started by AeroBar, Aug 22, 2009.

  1. AeroBar macrumors 6502a

    Jan 21, 2009

    My iMAC has two firewire 400 ports.

    I going to buy an external drive for storing and accessing my iTunes and iPhoto libraries and camcorder footage for editing with iMovie - I want this connected to the MAC all the time so I'm going have this connected to one of the firewire ports - leaving the other free for my camcorder.

    but I am going to have to buy another external hard drive soon that I also want to be connected to the MAC at all times.

    if I connect two external hard drives to the same firewire port via a firewire hub will this slow the performance of the two hard drives (or indeed the computer itself) ??

  2. kilowattradio macrumors regular


    May 11, 2009
    The only time you would notice a slow down is if you are accessing both HDD at the same time and a large amount of data is being transferred.
  3. cube macrumors G5

    May 10, 2004
    You shouldn't need a hub if one of the drives has 2 firewire ports to daisy chain (usual).

    The 400 Mbps of bandwidth will be divided among whatever is transferring at the same time (camcorder, disks).
  4. Pomeroy macrumors 6502


    Sep 27, 2008
    You shouldn't need a firewire hub. Every firewire drive I have has 2 ports and firewire can connect up to 63 peripherals in a daisy chain.
  5. AeroBar thread starter macrumors 6502a

    Jan 21, 2009
    for example I can't listen to iTunes on one while importing video or working on iPhoto on the other :(

    do you guys mean I can connect a second hard drive to the MAC via the first hard drive??
  6. jackerin macrumors 6502a

    Jun 29, 2008
    Yes, you can connect multiple devices to one Firewire port on your Mac (it is not an abbreviation) using daisy-chaining.

    I've myself got one audio interface and three external harddrives connected via the one FW400 port on my Mac mini; as each device has two FW ports there's no problem. (Though if one of the devices is bus-powered I think it's best to put that first in the chain.)
  7. zedsdead macrumors 68040

    Jun 20, 2007
    Are you sure you have two Firewire 400 ports and not one firewire 800 and one firewire 400?

    Either way, you can simply daisy chain the hard drives and any camcorders through one port. A hub is not needed and the performance will not degrade unless you mix 800 and 400 on the same port.
  8. gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N
    It won't have any noticeable affect on music playback, as that's running at a relatively low data rate.

    I have the single FW800 port with 5 drives and a DL burner daisy-chained. The first three are FW800 and are had the head of the chain. I get full speed out of those, unless, of course, they're moving data to one of the other FW drives.

    Aside from the speed, daisy-chaining is the other great advantage of FW over USB2.
  9. Sirmausalot macrumors 6502a


    Sep 1, 2007
    From what I understand, your entire chain (including the first two devices) are running at 400 (assuming the DL is 400 and on the same chain).

    Also, the OP should make sure the HDD are FW 400, 800 AND USB so as to maximize options depending on real world issues and eventual computer upgrade

  10. gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N
    No, not true: when using the FW800 drive(s) to/from the internal, I get exactly the same speed I would if it were the only drive on the port. That speed is pretty much the fastest real-world FW800 speed one can expect.

    The FW800 drives are the first drives in the chain. This is a quick & dirty test I did recently (on my 17" UB MBP):

    Tests on a ~800MB DMG file (the 10.5.7 combo updater) to/from internal 320GB 7200RPM (WD Scorpio Black) (just using Activity Monitor for measurement):

    Seagate FreeAgent Desk Mac FW800 1TB(first in chain)
    read: 68MB/s
    write: 68MB/s

    Seagate FreeAgent Pro FW400 750GB(about 3rd in chain, after two other FW800s)
    read: 36MB/s
    write: 36MB/s
  11. AeroBar thread starter macrumors 6502a

    Jan 21, 2009
    thanks everyone

    yes, I know that:rolleyes:. but I'll call it a MAC if I want to:)

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