USB transfer speed query

[AshleyC]

Whats going on here, ive got a Sandisk USB3 stick and when copying a large file to it i get this



Its starts off fast as anything as you would expect with usb3 and then plummets. If i use a micro sd card the speed is constantly fast across the copy, its just with the memory stick that it does this. It consistently does this, starts off like lightning and then half way through the speed cuts down to about a third of the start speed. Is it broke?

 

[Steeps]

It's not broken, the controller on the usb stick will reduce the speed after the "burst" to prevent overheating and damaging the usb drive. I've got some small metal usb sticks that do exactly the same and you can feel how hot they get with large writes to the stick.

 

[AshleyC]

Oh OK thanks, kinda defeats the point of the fast port though if it throttles it. At least memory cards stay at full speed.

 

[Steeps]

The memory card reader has the controller for reading/writing to memory cards rather than the cards themselves. Fast USB sticks are still great for reading data/writing smaller amounts of data fast. If I want to back up a set of photos from a session it can be done before throttling kicks in and it's quick, but if I want to backup a month's worth of photos at the end of the month then it will throttle.