It’s not easy to tell just by looking at the drive. The big difference between USB 2.0 and USB 3.0 is the reading and writing speed. What i recommend is using actually a software to measure the speed of transfer between the designated USB drive and a SSD. Why a SSD ? You shouldn’t have any bottlenecks in measurement while you do the benchmarks. If you’re gonna use a standard HDD, you could have some erroneous measurements.
I know, this method is not perfect but you can easily see how your drive will perform while reading and writing files to and from it. While having this in mind, i will recommend you some software that will do this job for you.
The first software is USB Flash Benchmark, which is decent for what can do, and it comes with a portable version. When you start this software, select the drive you want to measure, then hit the Benchmark button.
When the benchmark is complete, the software will pop-up a window with results speed, including of course, the read/write speeds with a nice graphic.
Our picks is the Crystal Disk Mark. You can customize completely, you can also build your own tests for various purposes, picking the file size for tests and if you want sequential read orrandom read with blocks of various sizes.This piece of software also come as standalone installer or portable version, leaving this option to you. We also recommend you to use the portable version instead of standalone version. The software makes you install some other crappy and unwanted software so it’s better to stay with the portable.
Even if you don’t get too much of what we’re saying here, we still recommend you this one, it’s the best we’ve seen by far (free of charge). Just a reminder, USB 2.0 speed goes to 7.9 MB/s to 9.5 MB/s in write speed. USB 3.0 goes from 11.4 MB/s up to 286.2 MB/s depending on the drive, producer, memories, connector and so on. Don’t expect too much from a cheap USB 3.0 drive, but definitely you will have better speed than any 2.0 USB drives. Having this figures you can see where your USB drive stand.