Dynamic Segmentation and Performance

IDM Features

• Dynamic file segmentation that uses in-half division rule
• Full reuse of connections that have finished downloading of assigned segments without additional connect and login stages
• Selectable timeout time and number of connections to tune IDM to your particular connection type

Dynamic file segmentation and connection reuse

Internet Download Manager has optimized file download logic. IDM divides downloaded file on file segments dynamically, unlike other download accelerators that divide downloaded file in segments once just before download process starts. Dynamic segmentation gives significant download performance improvement. When file download starts, it's unclear how many connections may be opened. When new connection becomes available IDM finds the largest segment to download and divide it in half. Thus new connection starts downloading file from the half of the largest file segment. IDM minimizes the time needed for negotiations with servers and keeps all connections busy.

On a progress bar pink lines show start positions, blue - downloaded segments, white - the segments to download.

Once a connection has downloaded a segment (when blue bar comes to a pink line) and if the next connection has not started to downloaded its segment yet, IDM reassignes the segment to the first connection. If the next connection has started to downloaded its segment, first connection helps other slowly working connections by dividing the largest segment in half. IDM won't divide the segment only when its size is too small for this connection type.

When connections have finished downloading all segments, IDM will assemble segments into one file.

IDM saves all file positions several times per minute. Thus after you stoped/paused downloading or even after unexpected power shutoff, IDM will resume download and assemble file correctly.

Pink lines on the picture are new start positions after Resume