Dropped Frame Rates During Boss Fight

Currently running an SLi setup on my PC. The door to boss rooms are causing a massive loss in frame rates. Specifically the Purple gating door. When I can pan to not view it, frames return to normal so it is something specific to this effect.

Disabling SLi does not resolve the issue. Haven't been able to find a setting or adjustment to fix the issue yet. Currently run 60fps in every area except on bosses. The effect drops to 30fps and is almost like slow motion. Any advice or fixes.

All drivers are up to date, and SLi profiles are on default.

AMD 8350 @ 4ghz 8-core
2x Nvidia GTX 970
16GB DDR3 1866 (PC3 14900)