Review on Strontium Nitro 32GB Micro SDHC Memory Card with Adapter - High Speed, 85MB/s UHS-I U1 Class 10 for Smartphones, Tablets, Drones, Action Cams (SRN32GTFU1QA) by Ron Turner

Bought this microSD card out of curiosity when it was on sale. The card is advertised as a class 10/U3 card, so it must support at least 10 MB/s when writing data. Running Crystal Disk Mark shows pretty good sequential read/write performance, which compares somewhat favorably to the 4 year old 64GB Samsung Pro microSD card I had idle. However, I was trying to transfer a large 3.5GB data file to my Strontium Nitro A1. recognized the problem. The card appears to deliver the advertised write speeds for relatively small files, but continuous writing to the card indicates that write speeds can drop to 1MB/s or even lower as I've seen in my testing. This can be a problem if you bought this card and think you can record long videos with it. When I run the same test with my old Samsung card, it shows that it doesn't suffer from the same problem. Conclusion: Don't buy if you want a microSD card that always supports Class 10/U1/U3 speeds. This should be fine if your normal usage is mostly reading, or if your entries are limited in size and duration. The card freezes after a few seconds of recording.