Slow download speed

I have a 1.1MB/s download and i don’t get why the launcher uses 600kB/s and i clearly see on my Cfos Traffic snapping software that the launcher is using 1.1MB of my download bandwith, but in the launcher is clearly using 60% of that. where the other 40% is being used? the time that takes to download corresponds to what the launcher saids but also my Cfos software shows the correct values, i’m start to thinking that something on the download service is loosing data packets.