As we have found out, there is indeed excellent compatibility between USB 2.0 and 3.0 devices and controllers. USB 3.0 drives are often faster when connected via USB 2.0 than native USB 2.0 products. The unpleasant exception was the Kingmax drive which had a poor speed of writing medium and small files, but its performance wasn’t any higher on the USB 3.0 controller.
Moreover, USB 2.0 drives can get much faster if you connect them to a USB 3.0 controller as the Corsair drive showed. We should acknowledge the EtronTech controller’s excellent work, especially as USB 2.0 mode isn’t a priority for it. It delivered high USB 2.0 performance compared to Intel’s USB 2.0 controller which is considered rather fast.
Connected to the USB 2.0 controller, the two USB 3.0 drives that we tested were about as fast as one of the fastest native USB 2.0 drives, the Corsair Survivor GTR. It must be noted that the Kingston DataTraveler Ultimate 3.0 was somewhat slower than its opponents, especially when reading small files.
When it comes to writing via USB 2.0, the Kingston was unrivalled with small files. It was twice as fast as the Corsair Survivor GTR which was second. The Kingmax ED-01, being good when reading via USB 2.0, can show a high speed of writing with large files only. It was much slower than the Kingston and Corsair when writing other files and was even outperformed by the humble ADATA in the MP3 pattern.
When connected to their native USB 3.0 interface, the Kingston is faster at reading large and medium files whereas the Kingmax reads small files better. The Kingston is also unrivalled in terms of writing, outperforming its opponent by 50% when writing a single large file. The gap is even larger with small and medium files.
Overall, the Kingston DataTraveler Ultimate 3.0 delivers excellent performance when writing files of any size, which is its main advantage. On the downside, besides its big case and high heat dissipation, is the low speed of reading files, especially small ones, in USB 2.0 mode. This drive may also require additional power for USB 2.0 connection. It is not handy to carry a rather big flash drive together with a power cable.
Well, there is already a second generation of DataTraveler Ultimate 3.0 drives which do not need additional power when connected via USB 2.0. Their specs are even more impressive: up to 100 MB/s at reading and up to 70 MB/s at writing.
The Kingmax ED-01 has advantages of another kind. It never fails at reading (even in USB 2.0 mode) and has a compact case. Its price is going to be more affordable, too. However, you should be aware that this flash drive is very slow when writing small and medium-sized files.
Summing everything up, we can say that, even though USB 3.0 is undoubtedly faster than USB 2.0, the real performance of USB 3.0 drives depends not only on the interface but also on their flash memory and controller. If a flash drive slows down to below 1 megabyte per second when writing small files, the newer interface won’t save the day. In other words, USB 3.0 will surely help reach higher speeds of reading and writing large files, but you can’t be sure about small ones. And with the fierce price competition among flash drive makers, it is quite possible that we’ll soon have the same situation with USB 3.0 products as with USB 2.0 ones where there is one fast model to two dozen slow ones which cannot fully utilize even the decade-old interface.