USB 3.1 Spec Approved, Brings 10Gbps Speeds

The USB 3.0 Promoter Group announced on Wednesday (pdf) that the USB 3.1 specification is complete and will raise the SuperSpeed USB transfer rate up to 10 Gbps. The current USB 3.0 spec in use has a limit of 5 Gbps, thus the latest release not only doubles what's available now on installed USB 3.0 ports, but makes SuperSpeed USB more competitive with Intel's Thunderbolt technology.

Unfortunately, the news doesn't mean current USB 3.0 ports will get an injection of speed. The new spec will be fully backwards compatible with USB 3.0 and USB 2.0, but only new ports manufactured with the USB 3.1 spec will be able to take advantage of the new speed limit. When ODMs will implement the new spec into their designs is unknown at this point.

"The USB 3.1 specification primarily extends existing USB 3.0 protocol and hub operation for speed scaling along with defining the next higher physical layer speed as 10 Gbps," said Brad Saunders, USB 3.0 Promoter Group Chairman. "The specification team worked hard to make sure that the changes made to support higher speeds were limited and remained consistent with existing USB 3.0 architecture to ease product development."

Despite the USB 3.1 boost, Thunderbolt is still faster thanks to a speed injection of its own to 20 Gbps. It also enables daisy chaining, whereas USB supports hubs that route several connected USB peripherals through one port. While Intel has been heavily pushing the Thunderbolt tech as a high-speed I/O alternative since it was first launched in February 2011, adoption has been rather slow.

Back in 2012, Acer became the first PC maker to adopt Intel's Thunderbolt technology. But the company said just last month that it has dropped the tech from its designs, and will focus on USB 3.0 instead. It was presumed that Acer was well aware that USB 3.1 was nearing completion and planned to use the newer SuperSpeed tech rather than the more expensive Thunderbolt.

"We're really focusing on USB 3.0 -- it's an excellent alternative to Thunderbolt," said Acer spokeswoman Ruth Rosene. "It's less expensive, offers comparable bandwidth, charging for devices such as mobile phones, and has a large installed base of accessories and peripherals."

Meanwhile, Intel seems to be supporting the new USB 3.1 spec despite its Thunderbolt efforts. "The industry has affirmed the strong demand for higher through-put, for user-connected peripherals and docks, by coming together to produce a quality SuperSpeed USB 10 Gbps specification," said Alex Peleg, Vice President, Intel Architecture Group. "Intel is fully committed to deliver on this request."

Developer conferences regarding USB 3.1 will take place in Hillsboro, Oregon (Aug. 21), Dublin, Ireland (Oct. 1-2) and a two-day session during December in Asia. Additional information about these conferences can be found on the USB-IF website.