Multiple USB3 Busses, OSX


I’d be grateful for any help on this one. I would like to install two 10-port USB hubs on my iMac (OSX 10.9.4, 3.5 Ghz i7, 16 Gb) but I’m unsure of the viability of this. The CPU has four USB3 ports, but I’m pretty sure they share a single bus. I’d like to be able to keep numerous 7200 RPM hard drives mounted, though rarely would I be actively using more than one or two at a time. Assuming I’m not attempting to charge a phone (which I gather maxes out the current more quickly) is this practical, and if so, do they need to be the same manufacturer, and do I require a particular firmware or chipset? Thx



Currently there are some potentially serious issues with Mac OS X and USB 3.0 hubs with external hard drives attached. Sometimes users run into issues where the OS will improperly eject the drives which can cause data corruption.

At this time we cannot recommend such a scenario but I’d still like to answer your other questions so with that being said, 1 or 2 hubs being attached to the system is not usually a problem. Mac systems seem to handle USB resources better than Windows systems.

We would recommend to keep the hubs at least running the same chipset and firmware. It’s not usually a good idea to mix different hubs as you can have undesirable behavior.



Thanks Josh - this gives me a bit more insight into the shadowy world of USB hubs.