Torrenting slows down my network speed I've noticed that when I have Transmission running my network speed becomes very slow. Even if I'm only uploading data (the same is true even if the upload rate is low as 5KB/sec) via Transmission the download speed becomes very slow throughout the computer. It doesn't mattet if I'm browsing using Safari, streaming music in iTunes, if a software is upgrading itself etc they all become slow. As soon as I close Transmission everything speeds up again. 

I'm connected through my Airport time capsule. 

Cheers.

Edit: This is to clarify some things as mentioned in Tetsujin's response. 


I only get this problem when Transmission is running. Even if Transmission is downloading 0 KB/sec and uploading at 3 KB/sec I still have these problems, so it's not because I'm reaching maximum bandwidth. 
I'm actually running through a VPN so my ISP should not be able to see that it's torrent traffic (nothing illegal here, I'm using VPN because I like anonymity). Actually Transmission is running through a udp port that I opened via my VPN provider. I've also tried running it through a tcp port, same issues. I tried randomized ports, same issue.  
I've tried using other torrent software and I think this actually might be due to Transmission specifically.
This is not a answer but a comparison.

I had to use it to show screen shoots.

First here is my basis: (my WiFi connection)



Second here is a sample when downloading two large files (at same time). As you can see the download did not budge, so I am not at the limit.

First file is 853 Meg size while second is 442 MB. Both are downloading with about 160 KB/sec.



And I am using Firefox to access the download sites.

However my example is strictly downloading. And there is no limit on download speed. How ever there is a speed limit to Upload.  As you know Torrenting could be tricky since you are also uploading (sharing).

So if you can limit the number for Uploading, that also uses your Internet connection and can slow it down significantly.