External USB HUB's going slow

I've got 2 hubs that are USB 2.2. i only use one at a time, but both experience problems with slow writing speed to external USB drives.

i often have to write large amounts of data to these drives, and if that means when i have to write ~120GB it takes over 50 hours it's a bit of a joke.

Any known issues with iMac's?

iMac is ~ a year old and running the latest updates.

USB and even USB2 is not real crash hot on Macs. Firewire is the preferred option. External case connect by Firewire? If so use that with SuperDuper.

i never had this issue for the past 9 months i've had my iMac, it's just this 1 and a bit months that have been the issue. before with the same devices connected i always had a solid connection when ever.

Even with windows firewire is a better option to USB (if firewire is supported on the machine) because firewire has a constant transfer rate of 400MBs where as usb is a variable transfer rate at up to 480MBs

Gaz said:

I've got 2 hubs that are USB 2.2. i only use one at a time, but both experience problems with slow writing speed to external USB drives ... 120GB it takes over 50 hours. Any known issues with iMac's?

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Despite its shortcomings, USB is the most adaptable form of device connection. A quality, externally-powered USB 2 hub will plough through major file transfers eg. movies, in *reasonable* time (the definition of which depends on expectation).

2 Gb/hour (approx) however is unacceptably slow. Moving 120 Gb should, even with the 'variable' USB factor included, take perhaps 15 - 20 (30 max) minutes.

External USB drives in particular, if they're not self-powered, will suck a lot of power from your iMac port(s). A part-answer to that is to use high-powered (1000 mA) USB ports on an externally powered USB hub.

If your $$ allow, replace the external drive enclosures with firewire (or combo) ones. Just be sure to shop around for those that best suit Macs. Not all enclosures are created equal.