Dunno if this is fixed in 0.14.0 RC1, but in 0.13.3 either setting a download limit or reducing the number of active downloads only appears to do anything after all the downloads that were started already finish. I'm on Australian internet, so 512kb/s is literally half of my bandwidth on a GOOD day, and when I just started Knossos downloading something on a fresh install with 3 simultaeneous unlimited downloads it immediately chewed up almost all my bandwidth. I limited it to 512, then to 128, then reduced the number of actives from 3 to 2. It still kept the three active, with one going hammer and tong at ~700kb/s, and the other two using the rest of my bandwidth for ~100 on one and ~200 on the other. Only when the first was done did it register that I wanted it to only have two actives, and when there was one of the old unlimited downloads and one new limited to 128 download, the old one was sitting at around 900kb/s. Once it finished and the only downloads active were from after I put the limits on, then it started behaving. It's just that until the last of the original three finished, I had essentially 54k dial-up speeds back for everything else I wanted to do on the internet combined! Was an unpleasant reminder. And most webpages are a LOT bigger nowadays, so loading was taking even longer than they used to!
EDIT: Hm, interesting... Last night it was treating the download limit as a per-active-download thing, even once it opened new downloads - a limit of 128kb/s was the max for each download separately, after it started respecting that limit at all. After a restart, it's now treating it as a total-bandwidth-for-Knossos thing - a limit of 512kb/s and two active downloads sees one going at around 300kb/s and the other at around 200.