Increase Frame rate in map

[Digital Storm]

I have tried all the light optimizations and it still runs slow, it shouldn't its a really small level so far only like 3 rooms. Ive been watching the frames and they seem to spike and drop like one second the game will be running 50 fps just fine then suddenly drop to below 30 then spike back up to 50 or higher without me doing anything other then standing in the one place and it continues to do that the whole time while playing the level.