USB 3.1
In January 2013 the USB group announced plans to update USB 3.0 to 10 Gbit/s (1.25 GB/s).
[54] The group ended up creating a new USB specification, USB 3.1, which was released on 31 July 2013,
[55] replacing the USB 3.0 standard. The USB 3.1 specification takes over the existing USB 3.0's
SuperSpeed USB transfer rate, also referred to as
USB 3.1 Gen 1, and introduces a faster transfer rate called
SuperSpeed USB 10 Gbps, referred to as
USB 3.1 Gen 2,[56] putting it on par with a single first-generation
Thunderbolt channel. The new mode's logo features a caption stylized as
SUPERSPEED+. The USB 3.1 Gen 2 standard increases the maximum
data signaling rate to 10 Gbit/s (1.25 GB/s), double that of SuperSpeed USB, and reduces line encoding overhead to just 3% by changing the
encoding scheme to
128b/132b.
[57] The first USB 3.1 Gen 2 implementation demonstrated real-world transfer speeds of 7.2 Gbit/s.
[58]
The USB 3.1 standard is backward compatible with USB 3.0 and USB 2.0. It defines the following transfer modes:
- USB 3.1 Gen 1 - SuperSpeed, 5 Gbit/s (0.625 GB/s) data signaling rate over 1 lane using 8b/10b encoding, the same as USB 3.0.
- USB 3.1 Gen 2 - SuperSpeed+, new 10 Gbit/s (1.25 GB/s) data rate over 1 lane using 128b/132b encoding.
USB 3.2
On 25 July 2017, a press release from the USB 3.0 Promoter Group detailed a pending update to the USB Type-C specification, defining the doubling of bandwidth for existing USB-C cables. Under the USB 3.2 specification, existing SuperSpeed certified USB-C 3.1 Gen 1 cables will be able to operate at 10 Gbit/s (up from 5 Gbit/s), and SuperSpeed+ certified USB-C 3.1 Gen 2 cables will be able to operate at 20 Gbit/s (up from 10 Gbit/s). The increase in bandwidth is a result of multi-lane operation over existing wires that were intended for flip-flop capabilities of the USB-C connector.
[59][60]
The USB 3.2 standard is backward compatible with USB 3.1/3.0 and USB 2.0. It defines the following transfer modes:
- USB 3.2 Gen 1×1 - SuperSpeed, 5 Gbit/s (0.625 GB/s) data signaling rate over 1 lane using 8b/10b encoding, the same as USB 3.1 Gen 1 and USB 3.0.
- USB 3.2 Gen 1×2 - SuperSpeed+, new 10 Gbit/s (1.25 GB/s) data rate over 2 lanes using 8b/10b encoding.
- USB 3.2 Gen 2×1 - SuperSpeed+, 10 Gbit/s (1.25 GB/s) data rate over 1 lane using 128b/132b encoding, the same as USB 3.1 Gen 2.
- USB 3.2 Gen 2×2 - SuperSpeed+, new 20 Gbit/s (2.5 GB/s) data rate over 2 lanes using 128b/132b encoding.
In May 2018, Synopsys demonstrated the first USB 3.2 connection, where a Windows PC was connected to a storage device, reaching a speed of 1.6 GB/s average.
[61][62]
USB 3.2 is supported with the default Windows 10 USB drivers and in Linux Kernel 4.18.
[61][62][63]
