VRAM usage problem?

[itsallgoode9]

I'm rendering a pretty basic scene in Maya plugin. If I render at 8100 x 8100, the scene is using about 6.5gb of Vram. If I go any higher (i need to render at 8500px), I get an out of memory error, even if I have out of core memory turned on.

I exported this scene to standalone and in standalone, it's only using 1.7 gb of VRAM when rendering at 8500px

what the heck is up with this? Plugin issue or Maya issue? Scene issue?

System:
Octane plugin v3.06
Maya 2017 update 3
2x 1080 FTW gpu