Review on High-Speed Silicon Power 128GB CFast2.0 CinemaPro CFX310 Memory Card, 3500X, with Read Speeds of up to 530MB/s. Ideal for Blackmagic URSA Mini, Canon XC10/1D X Mark II, and other devices by Dink Rivas

I bought two of these cards and was only able to get them to work at 190MB/s write and 390MB/s read. Nowhere are 330 MB/s writing and 530 MB/s reading. I'm really not too surprised considering they only cost $90 each. They still work well and are faster than any $90 SD card. You work for what I need. I just wish they advertised a little more honestly.