Originally posted by MarkJerling The XQD card write speed is up to 1gb/s so a big step up from SDXC. But, the XQD card is also 50% larger and 80% fatter, so that will take up quite a bit more real estate in a DSLR.
I'd much prefer 2x SD cards to an SD card and another format.
The XQD transfer speed starts from 1gb/s (or 125MB/s); XQD 2 is capable of 1GB/s (just to clarify b vs B). XQD cards on the market offer write speeds varying from 80 to 400MB/s. The fastest SDs, "only" 300MB/s (and about maxes out the capabilities of UHS-II).
The UHS-III standard is capable of "only" 624MB/s, behind XQD 2. But, how much do we actually need until speed is no longer an issue?
As I said previously, Pentax could triple its current transfer speed by fully using UHS-I SDR 104. Supporting UHS-II speeds - not necessarily the fastest - would provide further boost. IMO this is more realistic to demand and expect, than going XQD.
Good point about size, however XQD is smaller than the CF; maybe they could make 2 of them fit without increasing the body size.