Were you using firewall software on your computer? If not then maybe you were letting in a bunch of traffic that the router's internal firewall has now put a stop to. Can't think of another reason why a router would speed things up really.
I use cans of air (just bought two today for that purpose, in fact) and they've always worked quite well. Just watch what you're spraying and get in and get out before the can starts wanting to freeze things.