Download speed drops shortly after program start

[hosinsky]

I am new at this and probably doing something wrong. I have been downloading a torrent for several days. I now find, that when I start the program the download speed rapidly climbes up to about 450 Kib/sec but after five or ten minutes it start dropping and finally stabilizes at a few Kib/sec. Stopping the program, waiting a moment and then restarting it gives me the 450 Kib for another 5 minutes.

The torrent has 3 seeds  and 0-3 peers

Thanks
Goran

[Tomaso]

If you haven't modified the max connection limit in Windows yet, then do this first.
XP-AntiSpy is a small tool that can fix this for you in a simple way:
http://xp-antispy.org/en/
(Start XP-AntiSpy and navigate to 'Special' > 'Connection limit')
Setting the limit to 100 connections should do the trick!

..when you're done, then reboot your computer and go to this page for instructions on "Optimizing qBittorrent For Speed":
http://www.techsupportalert.com/optimiz ... rent-speed

[ihavefleas]

New to the software or new to torrenting as a whole?

I never modified any max connections in Windows so I don't think that would be the problem. If you mean that you are new to torrenting then there's a few basic things to look for.

- If you have a router, make sure you give your computer a dedicated IP and open the router port to that IP to make sure others can connect to you.
- Make sure the software is Allowed by Windows firewall. (Generally when you start it for the first time a Windows pop-up will appear and you click yes.)
- Make sure the torrent you're after has a sufficient number of seeders when you download it. (Also, if you're downloading a torrent where the seeders are, say, on the other side of the world, you may not get a connection.)

The case could very well be that when you start the software you get a connection to a fast seeder and then the connection drops after a bit - either by that seeders bandwidth being sent to a higher priority or shutting down the software. Seeing as your torrent has only 3 seeders this I'm betting this may be it, especially if it's an older torrent.

Try grabbing another torrent with a number of seeders (even if it's one you don't want) to see if it maintains a higher speed.

[Splat]

If there are other peers who have already downloaded more of the torrent than you currently have your d/l speed might rise like that because, in-essence, there are more people for you to d/l from until you get up to about the % d/l that they are at. Then your speed will drop off because everyone is d/l from the same seeds.

[Tomaso]

[quote="ihavefleas"]I never modified any max connections in Windows so I don't think that would be the problem.[/quote]
The Windows connection limit is definitely a problem.
..Especially if you're running WinXP, where the limit is as low as 10!

[humpty]

[quote="Tomaso"]
The Windows connection limit is definitely a problem.
..Especially if you're running WinXP, where the limit is as low as 10!
[/quote]

The XP connection limit is a myth. There is no limit for established connections, only for 'half open' connections. And even that is 'per second'.

That is 10 half open connections are allowed every second before they are timed out.
The limit was imposed by MS$ in a futile attempt to stop DOS like attacks.
(Explained here)

10 'tryout' connections per sec is usually sufficient to get you going considering that most people are willing to wait hours for a torrent to complete. It will make little difference wether you set it to 10 or 10,000 after the first minute.

[Tomaso]

More information here, for those interested:
http://media.liacs.nl/medialab/docs/lml141.html

When the half-open connection limit is reached, new connections will be queued until some of the current connections are established. The 10 half-open connection limit applies to Windows, not just BitComet, so if BitComet is using all 10 half-open connections and you try to load a page in your web browser it may take a long time to connect, or even time out.

That's the problem that I've encountered myself.
..and that's why I've raised the connection limit on my system.
-Problem gone!

[humpty]

...so if BitComet is using all 10 half-open connections.. and you try to load a page in your web browser it may take a long time to connect, or even time out.

That's slightly misleading. If all 10 half-open connections are used, the rest are queued for the next second, when another additional 10 half-open connections are made available. This means if you have 100 peers in a row who didn't reply or didn't exist it would take 10 secs to get through them all, which is why a browser would probably time out. Most peers however do reply and do exist.

[Tomaso]

Who cares about those technicalities, really?
There's been a lot of controversy surrounding the subject, but as long as raising the limit actually solves a problem, I'm satisfied.
Before I raised the limit, I had a huge problem with time outs in my browsers while a torrent client was running in the background.
..Sometimes I couldn't even load a single page!
After raising the limit, this problem disappeared right away, and I've never had it since.