" A USB 2.0 port is able to deliver 0.5 A of power while USB 3.0 is able to output 0.9 A. This means two things: USB 3.0 devices are able to charge faster and USB 3.0 ports can support more power-hungry devices.
Samsung's Galaxy Note 3 is the first phone in the world with a USB 3.0 port, making it ideal for comparing USB 2.0 and USB 3.0 charging speeds.
We first connected our Note 3 to a desktop computer's USB 2.0 port and recorded the time it took for the phone battery to charge from 0 to 100%. The same process was then repeated with a USB 3.0 port and a wall charger.
7 h 48 min
5 h 8 min
2 h 15 min
Take-home lesson: If you're using a desktop or laptop computer to charge your devices, then USB 3.0 will save you a good chunk of waiting time. However, USB 3.0's improved charge speed still pales in comparison to a wall charger (Note 3's default wall charger is rated at 2.0 A)." -'Build Computers'
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