Lag spike when streaming?

deffy

Hey guys i know this is maybe a bit off topic but i have about 16 mbps upload speed using fiber op internet, when i'm not streaming i don't lag what so ever, when i start to stream it runs smooth, after about 20 seconds i hit a huge lag spike that lasts about 4 seconds. It goes away and reoccurs every 20-30 seconds. I have a Asus ROG gaming laptop with an i7 and about 16 gigs of ram, and like i said fiber op internet, why am i getting this?