The rear yellow usb plugs on Lenovo laptops must be 2.0 and can be plugged in to supply power when the computer is off. The black ones are mostly USB 2.0. the blue ones must be 3.0. but note that some of the black ones with the logo SS (upper speed) are also USB 3.0 ports. the 2.0 and 3.0 ports have the same interface form, but the transfer rate is different, and 3.0 is faster. the black ones are not USB 2.0 ports, and the black ones are not USB 3.0 ports. Specific differences are:
1, contact piece method of differentiation: USB 2.0 only 4pin metal contact piece, while the USB 3.0 has a 9pin contact piece, the front 4pin and USB 2.0 is one to one, the rear of the 5pin is exclusive to the USB 3.0.
2, the logo differentiation method: according to the symbols next to the jack to distinguish, as shown below. USB3.0 "SS" stands for "SuperSpeed"
3, USB 3.0 standard B-type interface size than USB 2.0 is larger, the color is also blue. The upper part is more prominent, accommodating the new 5-pin contact patch, which USB 2.0 cannot access. This is better to distinguish. It won't be confused with USB 2.0's.