Of course without caching solution your limited for interior. But to be fair use Corona in a pure path tracing way and you will see how much we currently loose or gain.I don't know for sure, but 1080ti is a pretty powerful card. And If this was 4K we're talking close to 4 hours of rendering..?
But even with corona you can get pretty high render time look here bertrand benoit kitchen on bi xeon workstation took 4hours for 2K.
Bertrand wrote : There was relatively little post work done to them other than running them through ArionFX for some nice glows, levels adjustments and film emulsion effects. Beyond that, not much to say about this relatively simple scene, which uses a mix of new and re-shaded V-Ray assets. Render times oscillated between 2 and 4 hours, with the shots with heavy DOF taking quite a bit longer to resolve fully. Hope you like these.