USB 3.0
PQI advertises speeds of up to 210 MB/s read and 80 MB/s write. ATTO paints a similar picture, as the drive breaks the barrier advertised in write speed but falls short of 200 MB/s in read performance by clocking in at around 193 MB/s. HDTach, however, shows a different picture with performance. While read is similar to what is achieved in ATTO, write performance is only stable at 80 MB/s write for the first 500 MB or so before becoming a wild mix of spikes and dips between 15 and 130 MB/s. What PQI advertises is certainly not untrue, but write performance averages out to 43 MB/s.
In comparison to other USB 3.0 devices, the PQI Tiffy manages to take the third fastest spot in terms of average read performance, which is excellent for such a compact device as this one. On write speed, the Tiffy rests right in the middle of the spectrum. In the end, the USB 3.0 benefits the drive and is not simply a selling point on paper.
USB 2.0
Looking at USB 2.0, we see a similar picture as with 3.0. The read performance is quite constant around 35 MB/s, maxing out the interface can offer, while write speed is all over the place with an end-result of 19.5 MB/s. I would have hoped to see the USB 2.0 interface bottleneck here, but the Tiffy unfortunately has a slower average write speed.