Is it a myth that: the more we seed in bittorrent, the faster our bittorrent downloads?

If i stop all my seeding, will my downloads slow down?

  • Depending on the bittorent client, not seeding something your are downloading can slow your download speed for that download. The client sees you as an unhealthy part of the swarm. This is on a per download basis. I suppose you could overload your hardware (hard drive read writes) with too many connections. – Moab Aug 10 '11 at 16:03
  • To maximize download speed, a good upload bandwidth helps - it frees up the upload bandwidth of peers for you. Take a case of 10 peers with a fixed upload bandwidth and 9 peers downloading. These 9 would hog all uploaded data. If you upload your chunks, it has the effect of freeing up their upload bandwidth so, you can download the chunks you do not have. This would be valid in a case where few peers in the swarm have the complete copy - most peers are in for a hit & run. – Lord Loh. Jan 20 '20 at 4:16

You'll have to distinguish between a torrent with many seeds and a bittorrent client which is seeding many torrents:

  • If you download from a torrent with many seeds you'll probably download faster than from a torrent with few seeds.
  • If you're seeding many torrents while downloading a torrent the seeding while take up some bandwidth and thus you'll probably download slower than if you weren't seeding many torrents.

Note that the bandwidth taken by seeds are mostly upstream so it doesn't make a great difference to download speeds which mainly depends on downstream capacity.

Also note what TookTheRook mentioned about etiquette. If you look at it in terms of give and take you should at least upload enough to reach a 1:1 ratio (that is, so that you've uploaded as much as you've downloaded).

  • how do i see my ratio? – Pacerier Aug 10 '11 at 18:35
  • i just read this article. userpages.umbc.edu/~hamilton/btclientconfig.html which claims that we will get penalized if we do not seed? is it reliable? – Pacerier Aug 10 '11 at 19:21
  • @Pacherier Many clients allows you to see the ratio per torrent as well as for the total. – N.N. Aug 10 '11 at 20:15
  • @Pacherier About getting penalized I suggest you start another question. – N.N. Aug 10 '11 at 20:16

Not seeding torrents can slow down your speed depending on if the BT server or other clients perceive you as a leech - and hence give you reduced priority on their upload slots.

Seeding can also slow down your download, atleast 2 cases are:

  1. You max out upload speed and even the acks from the downstream get delayed, causing senders to throttle downloads to you believing that it is not getting through
  2. The net connection is so fast that the machine itself struggles to fill the available bandwidth and slows down (think Internet2 or similar 1gb+ upload bandwidth on anaemic laptop)

Case (1) is more likely to happen, just cap the BT upload at say 80-90% of your upload bandwidth and it'll be fine.

  • how do i check if i'm penalized? – Pacerier Aug 10 '11 at 18:37
  • Don't know of a consistent way to check, uploading clients won't all be the same and have differing behavior. Maybe reduce the upload bandwidth allocated to a particular torrent and see if you notice a reduction in download speed (easy, but unreliable - speed can also be lower because you completed more blocks and less people have remaining ones). That said, unless there is a pressing reason you should try to upload at 1:1 ratio if possible imho. – Alok Aug 10 '11 at 19:48

No seeding other files won't increase your download speed. However, its good etiquette to seed. The more seeds you have for a file, the faster the download. So you would be helping someone else with the same situation as yours.

  • 3
    Actually upstream and downstream bandwidth don't generally compete. There will be a slight overhead to seeding (as packet requests arrive over the downstream path) but generally seeding wouldn't cost you any appreciable download speed. Might violate your ISP agreement, of course. – CarlF Aug 10 '11 at 15:46
  • i just read this article. userpages.umbc.edu/~hamilton/btclientconfig.html which claims that we will get penalized if we do not seed? is it reliable? – Pacerier Aug 10 '11 at 19:21

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