Problems with LAN (laggy as f*** for all but the host). [v1.1.4.1]

Hey

I am well aware that there are plenty of threads about this but anyways, me and my mate is trying to play via LAN through Hamachi and it isn’t a problem for any of us to see each others game or join it, everything works as it should right there. Our problem is that when ever we leave a town in a multiplayer game the one who isn’t hosting starts to lag insanely for 5-20 seconds a time for atleast 80% of the session.
My question is: Is there anyone out there who know how to fix it or know if v1.1.4.2 will fix it? Have read (almost) every thread I have found about this issue and nothing works. The first time we played multiplayer everything worked fine, no lag for the entire session (think we played for 4-5 hours straight) but the second time (3 days ago) and the last couple of days GD multiplayer has been unplayable.
And for the record, my pc is not a shitty one, neither is my internet connection or my router. We have opened up for the game in our firewalls, etc etc.
So basically I just want to know how YOU (the reader) fixed this problem IF you of course had multiplayer lag problems.
And btw, there is really no need to come with an answer which states that there is no pc spec or anything like that missing. I really just want to hear what other people have done to fix this problem.

//cheers

Why aren’t you on v1.1.4.2? That’s the latest version of the game.

Have you tried the usual stuff.