Before I start I am sorry if this is posted in the wrong spot. When playing League of Legends I usually get a 60-70ms latency ping/lag. When someone starts downloading something in my network, it spikes like mad (obviously), is there anything to optimize it so that it can cut the ping so that it would be equal or something? As in lowering it a bit while the downloader can still have a good speed.
If you are using wireless there is not a lot you can do. Mostly this is not so much they are eating all the bandwidth it is they are interfering with you. Games need very little bandwidth they just need it to be very consistent. Wireless only has one device that can transmit at a time including the router. So even with just a single PC and a router you get overlaps and the more PC you have the worse it gets.
Now if you are running on a wired port you can try the QoS settings. You need one of the better routers that can place a hard limit on traffic that is not yours. Ie If you have a 10m internet you say all the machine in class low can only use 6m leaving 4m for your gaming machine. The ones that cannot place a number limit on do not work well. Even then this feature only can limit certain types of traffic. Bittorrent tends to not be controlled well but more normal things like video streaming and normal download work OK with the QoS.
Again it does not pay to try to mess with the QoS if you are using wireless.
You might want to try Latency Optimizer from Badosoft to optimize (lower) your ping / latency. http://www.badosoft.com/latency-optimizer.php
Keep in mind that your bandwidth is limited, so if there are many downlands going on there isn’t much you can do. Best bet is to limit the bandwidth of the other users and optimize your Computer, internet connection settings and Operating System to perform faster!