usb hubs: Powered vs Unpowered
With an unpowered hub, each device has to share the power supply and bandwidth from the computer’s USB port. This means the power and bandwidth are the same no matter how many devices are connected.
Low-powered devices like mice and keyboards will work, but you will find that high-powered devices like webcams and external hard drives may fail to work or generate error messages if the USB hub does not have the correct amount of power to operate.
When you have a powered USB hub, the allocation of electric power means that any device connected to it will be relatively unaffected. If you’re looking to connect multiple high power consuming devices, you should consider a powered USB hub. We believe the best hub is one that allows multiple device connections and can maintain high data transfer speed and connectivity with ease. Also note that any device that is connected to your hub, but is not being used, will not draw power.
Computer USB Port
Keyboards, mice, flash drives, low power devices
Printers, external hard drives, high power devices