Yeah I spent all day fiddling with settings. What finally worked for me was editing the "Torch2" Light setting in the Construction Set. Uncheck "Dynamic," Check "Spot Light." I also edited the area of effect down to 256 for good measure. In Maskar's Overhaul (in case anyone else who reads this is using it), I set torch brightness to -1 so it would be unaffected by the mod. I loaded the esp after my bashed patch just in case and voila, no torch FPS drops in cities anymore. The torches look a little worse, but honestly not by much. They still cast lights too. You can also turn off or reduce flicker in the same window in Construction Set. Also, in case you're using Martigen's Monster Mod, disable City Defenses and Lantern esps. Those destroyed my city frame rate. Hope this works for you.