Ive had the same problem with terrian certain terrain (probably sheep) hits my system almost as bad as flying the smoke of a severly porked base. trees don't seem to be a problem neither do beach obsticles. be nice two if we have a smoke slider limiting the number of smoke piles to say all to 1st newest and set smoke times like say defualt to 1 minute. Iam on a perty fast machine and In normal flight I get up to 80fps on this build (use to get over 100).