FPS black hole Mercy

There's a very bad FPS black hole that sinks me from 40 FPS to 15 FPS in mercy.

If you start at the south trainer and look east, you'll see the sink very easily.

I traced it down to just east of loc: -3590, 10, 195

Whatever is rendering near this location seems to compound.

At first I thought Fort Cerberus was causing the sink; that somehow it was rendering behind everything, but that's not the case. I can stand at the above location and look up at it and I hit 50 FPS.

Since this location seems to take up 15 FPS on its own. The drop to 15 FPS at the trainer would probably only drop to 30 FPS which is reasonable during regular play. ( I average 40-50 FPS).

This compounds with Shadow Maps. (the above FPS considers shadow maps in use), but I noticed I get an FPS drop without shadow maps turned on (only a slight one though).

Thanks.