I know also make sure your in game options are correct to, I know on my crappy PC, when in Hyldaa i Have to lower the distance way down, just remember to bring it back it back up when your out of hydlaa cause it makes it easer to see father, and make sure your FPS did not get messed with (for some reason mine has a time or two..I swear a little leprechaun or gnome logs on and plays with settings at times) but yeah if that's too low it will cause bad lag, your best bet, my guess would be to remove the grass and maybe even get more RAM, PS takes a lot of RAM.