Card is Lexar Professional 1000x microSDXC 128GB UHS-II/U3 (Up to 150MB/s Read) W/USB 3.0 Reader Flash Memory Card LSDMI128CBNL1000R.
The mp4s are playable directly in a computer at first but then something causes the card to stop being readable. I also cannot transfer all of the files from the card to a hard drive without the card crashing out. I've had similar problems both with a Windows 10 PC and a Mac.
Afaik, everything is recorded at the same speed.
I did format this card in the camera before using it for the first time.