It is worth noting that USB 3.0 has been officially rebranded as USB 3.2 Gen 1, which maintains a speed of 5Gbps, while USB 3.2 Gen 2 and Gen 2x2 are the new high-speed standards, with transfer speeds of up to 10Gbps and 20Gbps, respectively, and the prerequisite for high-speed transfers is that the device, interface, and cable support the dual-channel mode, which is usually only available for USB-C interfaces. In addition, USB 3.2 Gen 2x2 achieves high-speed transfers only if the device, interface, and cable support dual-channel mode, which is usually only available for USB-C interfaces.
Speed Differences
USB 3.0 (Gen 1): Theoretical transfer speed is 5Gbps, and in practical scenarios, the transfer speed is around 400 - 500MB/s.
USB 3.2 Gen 2: Theoretical transfer speed 10Gbps, in real scenarios, the transfer speed is up to 800 - 1000MB/s.
USB 3.2 Gen 2x2: Theoretical transfer speed 20Gbps, actual transfer speed about 1500 - 2000MB/s. Note that the actual transfer speed will be affected by various factors such as device performance, cable quality and file type.
Compatibility
USB 3.2 is backward compatible and works with USB 2.0 and USB 3.0 devices. However, in order to realize high-speed transmission, not only the interface of the device must support it, but also the cable used must support the corresponding version. USB 3.2 Gen 2x2 is usually only available through the USB-C interface and requires an active cable.
Interface Formats
USB 3.0 (Gen 1) and Gen 2: can be realized via the blue Type-A connector as well as via the Type-C connector.
Gen 2x2: Typically only supports the Type-C interface and requires support on both the device and host sides.
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