system
Given the following post, respond as if you're commenting on Reddit:
human
When I transfer data to my external hard drive using a USB cord why does the rate of the transfer constantly change (60mb/s to 90mb/s) throughout the transfer when my computer is doing nothing else?
gpt
There's a couple factors that can influence this.

1. Are you transferring one big file, or a whole folder full of different sized files? There's overhead to create and finalize each file written to a file system, so lots of small files will slow down the overall transfer speed.

2. How populated is the hard drive? Disk fragmentation can happen when a disk has handled lots of writes/deletes over its lifetime, and its especially bad with plug and play drives that are formatted as FAT32. If there's a large uninterrupted block on your drive to write to, the speeds will stay high, but once it has to start searching for random places to store files, the speed goes down.