As I said: Complete waste of money, therefore almost no data available. Why would anybody want to use such a high-priced card? As of today no device (apart from readers) will support UHS-II. (Not sure about a7s.)
Therefore: You're pioneer in unfamiliar area here. I have not a clue why the card seems to be such a failure with your equipment.
EDIT: Found some test data for this card. Seems to need an UHS-II reader to run well. Maximum speed using UHS-I compatible readers was limited to about 45 MByte/s. And some new cams are in fact UHS-II compatible: FujiFilm X-T1, Panasonic Lumix DMC-GH4