The internet connection might slow down due to the client consuming all available internet bandwidth for either downloads or uploads.
The client is set to use all available bandwidth by default. In most cases this doesn’t cause any problems since most files/file changes are transferred rather fast. However, transferring large files/large file changes may take some time, which causes the internet to be blocked during this period.
The client offers the possibility to limit the bandwidth usage of the client for up- and download as well as some pre-defined profiles with already configured values.
You can find more information as well as a detailed instruction on configuring bandwidth limits.