Bizfr's News | Technologies

According to the company, the SF-G Series UHS-II cards will be the fastest in the world, coming in at 300 megabytes per second read speed and 299 MBps write speed.

That 300 MBps isn't new -- the Lexar Professional 2000x was released in late 2015 with the same speed, but a write speed of just 260 MBps. It's this gap that Sony has closed, thanks to the UHS-II bus that pushed data transfer rates to a theoretical maximum of 312 MBps.
"The quick write speed supports maximum performance of digital imaging devices, contributing to longer continuous shooting of high-resolution images with UHS-II supporting cameras," the Sony announcement reads.
If it's high capacity and speed you're looking for, you might have to wait. The SF-G Series will only be available in 32GB, 64GB and 128GB capacities, launching in spring 2017.