How can I write to a USB 3 flash drive faster than 15 mb/s? I've got a USB 3 flash drive that should be able to write at about 50 MB/s, but I'm only able to write to it at 15 MB/s. I'm using a Mac Mini 2012, which has four USB 3 ports. I am connecting the flash drive directly to the Mac Mini, and not using a hub of any kind.

Are these normal speeds for the USB 3 ports on the Mac Mini 2012 when writing to a flash drive, or should they be much faster as I suspect they should? How can I get better write speeds to this drive?

The read speed for this drive is about 80 MB/s, so it's a bit more reasonable, although it should be 180 MB/s according to the specifications.
Depends on the speed of the flash. Most flash drives allow faster read then write since writing to a flash is a "destructive operation"

A site like http://usbspeed.nirsoft.net/ might provide further information.

As an example SSD drives are rates at a number of Input/Output Operations/s (IOPS) commonly read is faster then on even the best most expensive drives.