Some maps, like Hardins Pike custom battle, are really laggy while the other, like huge Antietam, are running pretty well. What I've noticed is that the laggiest maps have a lot of heavy cover (the one like on screenshot). Hardin Pike, Maryland Heights, Cold Harbor (right flank mostly) etc. I think it can be something wrong with that texture. Maybe it eats too much memory or something. Please, check it and fix if possible.