unplayable lag

[xfriedfishx 0]

I have played Day z for a while and have bad basically no problems with lag, but sometimes when i get close to cities i start to lag horribly. I know this is normal but it also happens when i am on a server for a while, the game will start out with no lag 40ish fps but after i play for about 10-20 min my frame rate goes down a lot. it gets to the point where i have to turn my graphics settings down to low and that still doesn't help(at that point im getting about 5 fps) is there a fix for this or something i can change to make it run better and i have already tried googleing it, and i have all the stuff in short-cut (ex. -nosplash). Also i play on single player with settings that are a mix of med/high. Thanks in advance for all the help:)

[xfriedfishx 0]

also this did not happen before 1.7.1.1