My Bittorrent, in working time, all time have a amplitudes, the cable connection from 600 -800 Kb, than in his pick, starting to slow down to zero, wait fo a long time, than start to download with 0,3 or 0,5 Kb. What's is wrong? Thanks.
What you are seeing is normal with torrents.
If I was you, I would double check that the port forwarding rules are there (or UPnP is working).
I have a gigabit internet connection and if a torrent is not very well seeded (not a load of other people with the file), the connection is usually VERY slow, where as I can download a well seeded file at many MegaBytes a second.
Torrents rely on other people having fast upload speed.
Your question isn't totally clear. If you are saying the speed drops and then remains low? If so, then it could be the ISP throttling the line (as an example). You need to perform some tests to find out.
If this is on a laptop (or if you have access to multiple networks), then try on a different network.
I also suggest you perform a speed test (Google speed test), make a note of the download and upload speed and then start a torrent download. When the torrent slows, try doing the speed test again to see if the issue is with the torrent download only (or not). If the speed test remains fast, the issue is then with the torrent or the program. If the internet is also slow, then it's the ISP (who you'll need to contact direct).
bittorent and utorent use p2p file sharing protocol. Meaning it gets the file from other users that have downloaded the file. From a ratio of 10, if 10 people has downloaded the file and only one out of ten is sharing it don't expect that your download speed it fast. That's why if you read comments on torrent site the most repeated comment is "PLEASE SEED" meaning "PLEASE SHARE THE FILE" in torrent software like you utorrent and bittorent and keyword is "UPLOAD". Some users after successfully downloading the file they stop it, not noticing that the ''UPLOAD" is still running. That's why your download speed is slow because other users don't upload it AKA ''SEEDING". It's not the fault of your ISP. But it's the fault of the users that have successfully downloaded the file and doesn't seed it.
Long story short, it depends on the external people seeding the same file at the same time.
This is not 100% effective and I agree with William Hilsum sometimes the ports can be deceiving, what you can do is port forwarding the router correctly. You can also test if the ports are forwarded correctly. Change the settings by going to Options>Preferences Change the port to something else and also make sure you "Enable UPnP port mapping", and "Enable NAT-PMP port mapping" Add exceptions to your firewall and make sure your firewall isn't blocking the ports which causes the internet and the downloading speed to go slow.