TorMonitor

Why is my torrent slow? 7 fixes for faster downloads on Mac

Updated 2 min read

Short answer

A torrent is slow when few peers have the data or when other peers can't connect to you. Check the seed count first, make sure the status bar says Port … open (turn on UPnP / NAT-PMP under Preferences ▸ Connection), add more trackers, check your Bandwidth limits and schedule, and with Pro turn on Fast peers only to drop peers that send almost nothing.

Torrent speed depends on the swarm more than on your internet plan. Work through these checks in order; the first two explain most slow downloads.

Steps to diagnose a slow torrent#

  1. Look at the seeds. In the torrent list, Seeds shows connected seeds and, in brackets, the swarm total, for example 3 (40). If the total is 0 or 1, the torrent is poorly seeded and nothing on your side will make it fast. Look for a better-seeded copy.
  2. Check your port. The status bar at the bottom shows Port 6881 open when other peers can reach you, or (no incoming yet) when they can't. With no incoming connections you can only reach peers who are themselves reachable. Open Preferences ▸ Connection and turn on Enable UPnP port mapping and Enable NAT-PMP port mapping, or forward the Listening port on your router.
  3. Add trackers. Open the Trackers tab. If trackers show errors or few peers, right-click the torrent, choose Add Trackers… and paste extra announce URLs, one per line. Then choose Update Tracker.
  4. Keep DHT and Peer Exchange on. Under Preferences ▸ BitTorrent, Enable DHT network and Enable Peer Exchange find peers that trackers miss (they're off by design for private torrents).
  5. Check your limits. Look at Preferences ▸ Bandwidth for a Maximum download rate, at Bandwidth Allocation… on the torrent itself, and at the Scheduler. The status bar shows any global limit in square brackets.
  6. Check the queue. If the torrent says Queued, raise Maximum number of active downloads under Preferences ▸ Queueing, or use Force Start.
  7. Drop slow peers (Pro). Under Preferences ▸ Bandwidth, turn on Fast peers only (downloads). Peers that stay below the Minimum download speed per peer (20 kB/s by default) after the Grace period for new peers (45 seconds by default) are disconnected, so their connection slots go to faster peers.

Also worth trying#

  • Protocol encryption: some internet providers slow down unencrypted BitTorrent traffic. Check the Protocol encryption setting under Preferences ▸ Connection and make sure encryption is allowed or preferred.
  • Global maximum number of connections: too low starves big swarms; too high can overwhelm a home router. The default is a good start.
  • Wi-Fi: a weak signal limits everything. Try a cable for large downloads.

Questions#

Why does a torrent start fast and then slow down?#

Early on you connect to the fastest, best-connected peers. Near the end you may be waiting for a few rare pieces that only slow peers have. Fast peers only helps here, and so does patience.

Does seeding slow my downloads?#

Uploading uses some of your connection. If your upload is saturated, downloads can slow too. Set an upload limit under Preferences ▸ Bandwidth (Pro) to about 80% of your upload speed.

What do the numbers in brackets mean?#

Connected (in swarm). 8 (127) means you are connected to 8 of the 127 peers the trackers know about.