well lot of things, not only the LWF check box (dont use it) it a "faked" LWF, some settings in DMC were a way high even with my 12core i took me a longtime to render it, so i made an optimisation of the scene, dont know whats the render time maybe few min
Linear workflow - when this option is checked V-Ray will automatically apply the inverse of the Gamma correction that you have set in the Gamma field to all VRayMtl materials in your scene. Note that this option is intended to be used only for quickly converting old scenes which are not set up with proper linear workflow in mind. This option is not a replacement for proper linear workflow.
ull see when i send u the scene