There are few, if any, host devices currently on the market that require or can even make use of so much speed — those that do are already using faster memory formats, like CFast 2.0 or XQD. SF-G cards will easily handle the demands of current 4K mirrorless cameras, of which Sony makes quite a few, but also pave the way for higher-performance models to come. Sony also states the high write speed will enable longer sustained bursts of high-resolution photos, but this will depend on the camera’s ability to keep up with the card.
One thing any user can get excited about, though, is taking advantage of that 300MBps transfer speed to offload data to a computer more quickly. Alongside the new cards, Sony has announced a USB 3.1 card reader specifically designed for this purpose — just keep in mind, a standard spinning hard drive might not even be able to keep pace with the card.
Interestingly, the SF-G series is not ushering in a new standard — it’s apparently not even part of the latest SD 5.0 specification. The cards are standard USH-II U3 cards. In fact, as DPReview pointed out, U3 offers only a guaranteed sustained write speed of just 30MBps. Sony claims the higher performance numbers of SF-G cards are thanks solely to the company’s unique firmware and a new algorithm that “prevents the decrease of data-writing speeds,” according to a statement. That would seem to imply that SF-G cards are designed for higher sustained speeds, not just brief moments of maximum performance, so hopefully sustained speed will be much higher than what the U3 designation specifies.
