My tests: So far, my fastest tested flash drive is a 32GB *PLATINUM* which reaches 260 MB/sec. reading speed on USB 3.0 . Writing should be above 200 MB/sec., meaning 20 seconds for 4 GB. A 128 GB SanDisk and 128 GB Intenso reach around 180 MB/sec., and a 64 GB Intenso around 60 MB/s. MicroSD cards of SanDisk and Transcend are in the 80 MB/s range. But not only speed matters, but also **stability**. Speed downspikes (testable using software such as *HDDScan*) are a warning sign of degrading flash storage, as it could indicate an attempted error correction. Often, it is successful. But too many minor errors together corrupt data.