I have a 15 inch MacBook Pro (model MacBookPro6,2) with 2.66 gHz Intel Core i7 and 8 GB RAM from mid 2010.

Right now, I use a LaCie Firewire 800 bus powered Little Big Disk Quadra which works well. There are two Firewire 800 ports on the Little Big Disk Quadra, so I am wondering if I can daisy chain another Firewire 800 bus powered external hard drive to it? Will the MacBook Pro be able to power both?



Yes - I have routinely used up to 4 self powered devices one one FireWire port.

Tom's hardware report that at idle most laptop sized spinning hard drives use less than 1.5W idle and less than 4W at peak - so firewire should start to run out of power between 8 to 10 drives chained together assuming your mac is putting out at least 80% of the design power and they don't all spin up at exactly the same time.

  • Macs give 8 watts. Have you had any issues with drives not being able to spin up at the same time? – malhal Dec 24 '15 at 17:37

Yes this will work. That's the point of firewire, being able to chain multiple devices off the single port. You might see some data speed slowdown if both devices are accessing the bus at the same time. But at 800mbit you'd have to be doing something pretty hectic for it to be noticeable.


According to Wikipedia each port should give you 45Watts of power, which should be enough to drive a second bus powered device.

  • Macs give 8 watts though – malhal Dec 24 '15 at 17:36

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