Is it worth buying a USB3 hard drive adapter compared to buying a USB2 adapter?
Let’s break it down.
USB2 can theoretically transfer data at 480 megabits per second (Mbps) or 60 megabytes per second (MB/s.)
USB3 can theoretically transfer 5 gigabits per second (Gbps) or 625 megabytes per second (MB/s).
Mechanical drives are limited by physics and usually can’t transfer faster then 180MB/s. SSDs are better at saturating the 3Gbps bus and newer ones are reaching the limits of the 6Gbps SATA bus.
SATA revision 3.0’s speed limitation is 6 gigabit per second (Gbps) or ~600 megabytes per second (MB/s).
Intel’s 540 SSD (2.5″) can do 540 megabytes per second (MB/s).
As an example Samsung M.2 SSDs can read at 3500 and write 2100 megabytes per second (MB/s).
So yes, a USB3 hard drive adapter is worth it! You will get around double the speed on a mechanical drive going from USB2 to USB3 however if you plug in an SSD you can get much faster speeds.