Sounds like it's one of your addons that's causing it, this map hasn't been updated in over 2 years.

addon issue, you may have too mutch addons, I have around 480 and I get 2fps, when I played breach ver with around 300-400 addons it was like around 15fps now it's 1fps. I guess only way to fix it is to uninstall useless addons or it's your pc just doodoo

simple fix without getting rid of addons recode the props so that there frozen and have less sides (make them have sides that are 2d not 3d) if you cant code just download a mod that gets rid of props when you arent looking

its cause the map is 800 MBS thats why i dont get big maps