Just received a 128 GB SanDisk Extreme PRO USB 3.1 Solid State Flash Drive. I wanted to check whether its speed really matches what’s advertised of up to 420 MB/s for read and 380 MB/s for write.

Benchmark Details

Computer Used: Lenovo Thinkpad X1 Carbon

OS: Ubuntu 16.04.3

Benchmark Tool: Standard Gnome Disks Utility

Features Tested: Read Speed, Write Speed and Random Access

Testing Samples:

• 100 samples, 100 MB each for read and write tests
• 1000 samples for access time

Results

Average Read Rate: 423 MB/s

Average Write Rate: 188 MB/s

Conclusion

The SanDisk Extreme PRO USB Drive Read speed is 420 MB/s as advertised, however, the write speed is much lower than the promised 380 MB/s. It’s a quite fast USB drive, especially for read, but the write speed is about half what SanDisk claims (although still very fast for a USB drive).