Bus or Brick? Maybe another stoopid newbie kwestion

Discussion in 'PowerPC Macs' started by magilla, Sep 24, 2013.

  1. magilla macrumors regular

    Aug 3, 2013
    Does running USB devices directly off the iMac'sG5's USB ports draw more power than plugging in a 4 or 7-slot USB hub to the Mac's USB port then running USB items from THAT or should I go with a brick-powered USB hub vs. a slot powered one? Power access isn't a problem - I have a 4-socket Isobar surge protected power source with 3 open sockets sitting right under the iMac so desktop/power brick clutter's no problem.
  2. DZ/015 macrumors 6502a


    Mar 23, 2003
    New England
    Any USB device draws the power it needs to operate, regardless of where it is plugged in. Plugging many devices into a bus powered hub can cause them to not operate as expected. Or not operate at all.

    If it is not a problem, use a powered hub.
  3. magilla, Sep 25, 2013
    Last edited by a moderator: Sep 25, 2013

    magilla thread starter macrumors regular

    Aug 3, 2013
    I guess what I'm trying to says is that if I have a (wired) keyboard (Apple) and a wired mouse (Logitech) plus a wired Epson printer and 2 USB external drives, the keyboard+mouse take up 1 USB port, the printer a second and I have to choose which of the external USB drives to run off of the last available USB port.

    Is it better if I get an EXTERNALLY powered (brick) USB hub, plug THAT into 1 of the iMac's USB ports and maybe run the 2 drives and/or Epson printer from that or get a USB port-powered hub and run things from THAT?

    I would think that running everything from the iMac's USB port(s) would eventually tax the system's processing power/speed.
  4. Intell macrumors P6


    Jan 24, 2010
    It won't be a problem for the iMac. It was designed for then all to be used at the maximum allowed USB 2 power spec.
  5. Anonymous Freak macrumors 603

    Anonymous Freak

    Dec 12, 2002
    1. Keyboard directly to iMac, mouse to keyboard.
    2. Pick the external drive you want the highest performance from - plug that directly into the iMac.
    3. Plug a hub (powered or unpowered) in to the third port, and connect the printer and the other hard drive in to that.

    As far as power consumption goes, (as in: electricity,) it doesn't really make a difference. The printer and hard drive (if the hard drive has its own power,) don't use USB power, so it doesn't matter, you won't over load even an unpowered USB hub. (You could plug the printer in to the second port on the keyboard if you really felt like it.)

    From a computer performance perspective, the iMac G5 can handle the USB processing overhead just fine - adding a hub won't make a difference.

    From the peripheral performance side, you need to know that each port on the back of the computer has a fixed amount of bandwidth, shared among all devices plugged in to it. So for best hard drive speed, you want hard drives plugged directly in to the computer if at all possible. If you plug both the printer and a hard drive in to one USB port through a hub, they will share that bandwidth. When you're not printing, you won't notice - the hard drive will have access to the full bandwidth. But when you are printing, access to the hard drive will slow down. (So if you don't mind the clutter of having the printer plugged in to the keyboard, that would actually be fastest - since you could then plug both hard drives directly in to separate on-computer ports.)
  6. magilla thread starter macrumors regular

    Aug 3, 2013
    THAT'S the kind of answer I was looking for! Thanks much - it explains everything I was wondering about in my own little old befuddled mind.:D

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