Tried the DNS fix you mentioned to no avail. For instance today my first 3 games were fine, this last game I just played... unplayable. Lag spikes that lasted like 10-15 seconds with only like 3-4 second intervals. Of course I made sure I had no torrents or anything like that running, disabled all my virus protection, windows firewall off, LoL ports forwarded in router, multiple release/renew ip's (this has usually helped in previous instances) and nothing.
Again I state that I never had this issue until that patch that was supposed to make things "faster/smoother". It also seems random, sometimes my first game is laggy, but afterwards it's fine. Then like today it's the last game after 3 that's hopelessly laggy.