After the initial full backup, only data blocks that have been changed will be uploaded to the Nexetic backup server. This is enabled by a method called data deduplication, which we use very efficiently. So, it is just small blocks of data being sent from your computer to our server, not complete files. Thus it is only taking a little bandwidth and won't interfere with your other internet usage.
It is also possible to use bandwidth throttling which means you can limit the bandwidth that is allowed for the backup service to use. You can do this in Bandwidth selector under Settings (in both client and control panel).