The recording speed is excellent. Even when shooting in full HD with my SLR.
If you often 4K movies faster memory card can be significant but personally it enough for me.
This is perfect for fans gusts thanks to a very fast writing. The reading is also faster.
On my computer I will write between 50 and 65 Mb / s reading and 65 Mb / s to 85Mb / s
Even with very heavy photos, sometimes more than 20 MB, I have never had problems with registration.
Very good buy I would not hesitate to recommend.