Sony claims its new SF-G Series UHS-II SD cards are the "world's fastest," touting write speeds of up to 299 MB/sec. Sony says it has provided custom firmware allowing faster-than-ever saves to SD cards.

For comparison, SanDisk's Extreme Pro SD UHS-II card is thought to be an absolute speed demon, and SanDisk claims its write speeds can reach up to 260 MB/sec. SanDisk's card and Sony's new cards have similar read speeds of up to 300 MB/sec.

The new cards may be of most interest to still photographers, who are looking to keep snapping off shots as their cameras write high-resolution images to storage media without getting bogged down by data buffering as it waits for the card to catch up. Super-fast bursts are fine and good, but it's not yet clear what sustained speeds the new cards may be able to deliver for video shooters — they bear the U3 speed classification, indicating a minimum sustained write speed of 30 MB/sec.

The new cards will be available with capacities of 32 GB, 64 GB or 128 GB and are expected to arrive this spring, along with a new high-speed USB3.1 Gen1 SD card reader, the MRW-S1, Sony said.