usb hub

  • Thread starter Thread starter rodchar
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rodchar

hey all,
i have a usb 2.0 hub and was wondering if i have 2 external drives connected
to it is there a performance hit?

thanks,
rodchar
 
rodchar said:
hey all,
i have a usb 2.0 hub and was wondering if i have 2 external drives
connected
to it is there a performance hit?

thanks,
rodchar
Click to expand...


The maximum bandwidth of the USB controller (for the port to which you
connected) does not change when you add a hub. You are using multiple
pipes but they connect to the same common pipe.
 
If both are transferring data at the same time, yes, individually not so
much. If the drives are USB powered and the hub does not have an external
power supply the drives might not work at all. Any other high bandwidth or
high power draw devices attached to the hub will cause similar problems (ie.
webcams, WiFi adapters, routers, scanners).
 
in message
are there any switch-type hubs out there?
Click to expand...

USB operates similar to SCSI. Devices get enumerated and each gets
its own channel (i.e., device number). You don't need switching.
It's already builtin. That still won't increase the max bandwidth for
the USB controller back in the PC to which you are connecting the USB
hub and/or USB devices.

See "The USB Process", section 4, at
http://computer.howstuffworks.com/usb.htm.

Each USB controller will have 2 ports and why you see them in pairs.
Both share the same controller and so both are limited by the
bandwidth of that controller. If you want more USB bandwidth then
check if your mobo has more than one USB controller. There may be
unused USB headers on the mobo for more controllers. Otherwise, get a
USB daughtercard to stick in a slot.
 
If you have a spare PCI slot you would be better off installing a multi-port
USB2 card to eliminate the issue.
 
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