Here’s where much of the nomenclature confusion starts. Apple devices actually charge at 2.1 Amps, more than four times the USB 2.0 specification. Yet, most modern devices only draw as much power as they need and can easily support higher-level current. However, they are technically outside the USB spec and risk blowing up a device if the circuitry isn’t expecting higher current levels. Some USB chargers can provide higher power levels, charging devices faster. While we’re discussing specs, we should mention that power specifications have never been hard limits they’re more like speed limit signs, showing the maximum safe power level. USB 3.0 allowed for dramatically higher power levels and faster data transfer, boosting them to 900 mA at 5V and 5 gigabits per second (Gbit/s), respectively. USB 2.0 also limited power to 500 mA at 5V. It upgraded USB 2.0, which was released in 2000 and allowed for only relatively slow transfer speeds of 480 Mbit/s. Released ten years ago in 2008, USB 3.0 was the third major revision to the USB standard.

Color of usb 2 vs usb 3