So my game had no problem booting since day one with SLI enabled.
Randomly about three days ago my game would not progress past the gearbox loading screen. It'd lock up - freeze - do a number of things except load. It even locked my computer up numerous times forcing a reboot
I'm unaware if AMD users are having this issue but after disabling SLI entirely from my system VIA the Nvidia control panel - the issue went away.
After searching google many other people seem to be having this issue. Considering I run my game @ 2560x1080 this is undesirable as now Huge unit caps seem to bring my FPS down to the 30-+ regions.