It was KTorrent! But to be fair I just arbitrarily thought that 30MB/s would be more than enough speed (at my place in France that's probably the fastest my internet connection is capable of), tried that, it worked, in a few seconds the file was there, and that was it. I didn't try to see how fast I could go before a crash, maybe if I would have set it to 100MB/s it would have still been ok.