Slowdown when someone else uses torrents but not all bandwidth

[pavichokche]

Hello, I firstly want to apologize if this question is too simple, but I couldn't find any detailed-enough answers to my exact question. So firstly, we have cable internet with 5 Mb/s download and 1 Mb/s upload speeds. The wireless router is a Netgear N600.There are three people on the network, only me and my mother use torrents, and there are multiple mobile devices connected at all times. I used to think that limiting the global download speed to 400-500 kB/s would be enough, using at most 2/3 of the total bandwidth we have, however the other users often experience an incredible slowdown still. Another example, actually my main motivator for wanting to solve this, is that when my mother is downloading at even half of the bandwidth and I try to play Minecraft, the lag is incredible. Also often my browser becomes incredibly slow (pages barely load) even though my computer is receiving bandwidth (for example Dropbox manages to chug along at 60-70 kB/s).

So my question here is: Would limiting the connections on my mother's uTorrent help at all, or is there any sort of other adjustment I can do on any computer or the router to speed things up?

Thank you !