Just received Lexar Pro UHS-II 64GB microSDXC. Did a write test from internal SSD to microSDXC and reversed it from microSDXC to internal SSD for read; six files totaling 6.1 GB
sustained write average of 57 MB/s
sustained read average of 125 MB/s
Fastest SD card I have ever used!
I saw some discussion about whether the Phantom can get by with a UHS-1 card. The 4K spec seems to call for a UHS-3 card. Wikipedia says:
UHS Speed Class 3 (U3) 30 MB/s 4K video files (UHS bus)
Class 10 10 MB/s Full HD (1080p) video recording and consecutive recording of HD...