The difference is -10mbit download speed. My DL is 50d and 5p, its 40d and 2-3p when Avast is running.
it makes searching on the internet slower, takes longer to load pages and it annoys me.
Sure some might say that 40 is still alot but I don't care. I didn't pay for Avast to get a 40mbit d speed when I've paid for my internet to have 50d speed.
If the problem can't be solved I would ask if theres a refund option. Otherwise if not, I'm done buying Avast products in the future and I have learned my lesson.