Improving speed and limiting bandwidth
PDM splits each file into parallel segments. Tuning the connection count and the speed limiter makes downloads faster without starving the rest of your network.
Connections per download
Set the maximum connections per download in Settings → Connection. More is not always faster — some servers drop excessive parallel connections.
Limit the speed
Use Settings → Download for a global cap, or right-click a single download and choose the speed-limit option for one file. When both apply, the lower of the two wins.
Why does one download use a single connection?
Multi-part downloading needs the source server to support HTTP Range requests and to report the file size. When it does not, a single connection is the correct behaviour rather than a fault. The download progress window shows which applies.
Put the temp folder on another disk
With several physical drives, place the temporary folder on a different disk than the destination so files assemble faster.