[Client] [ARAM] Butcher's Bridge not causing FPS drops, but Howling Abyss was.

I had assumed there was some unspeakable horror that made my Alienware randomly drop to around 45 fps in ARAM. When this new map was announced, I was excited but apprehensive about how my computer might handle it. Instead, I'm getting over 100 frames with no drops with the Butcher's Bridge map. What's up with that?

Repro:

1. Purchase an Alienware r7 with 16 GB of RAM, Intel i7-8700 CPU, and NVIDIA GeForce GTX 1080 Ti.
2. Play ARAM on Butcher's Bridge.
3. Observe the good frames, play the match best you can.
4. Finish the match.
5. Wait until Butcher's Bridge event is over.
6. Play ARAM on Howling Abyss.
7. Observe the random frame drops, some very severe. Play the match best you can
8. Finish the match.
9. Stare at your Alienware and wonder what happened for this disparity to exist.