Limit LAN upload speed (Ping Issues)

[jrwagh333]

When playing CS:GO my ping is fine, say 40ms.

When somebody on my LAN is transferring a file from my PC, it maxes out my connection and up's my ping to around 200ms.

Is there a way to limit the upload speed my PC provides to everyone else on the network?

 

[jrwagh333]

Yes the router has QoS but doesn't seem to make much difference.
No I don't want to buy a NAS, I don't want to spend money if I don't have to