When copying from USB or external drive, why does it starts very fast and suddenly drops transfer rate by up to 50% and stays there? Why it can’t be speed as in the beginning all the time?

Question

Is it a hardware limitation or calculation algorithm problem, until enough data is transferred to calculate exact speed?

In: 14

Answer 1

It depends on the type of file(s) and what else your computer is doing while the file is being transferred. A single large file will transfer faster than several smaller files that total the same amount of storage for example just due to the processes that take place between each file transfer. The first parts of the transfer may also be just copying metadata or pointers, which are practically nothing thus move quickly while the actual data takes significantly longer.
Additionally, if your computer is doing anything else, it may intermittently slow down a file transfer while those other tasks run.