Is there any solution to the cost of opaque (glass) materials for VR?


I work in the archvis field doing VR walkthroughs, My scenes were fine with the DK2, but the higher res and the FPS required for the vive, I’m struggling to hit the 90fps target. I’ve tried turning off all the common things (Lens flair, ssr etc) But when I GPU profile the thing that is the most taxing is the glass. Is there any low cost glass material? Or this is just something I will have to work around?

What GPU are you running? Transparency is always fairly taxing but once you add refraction and reflection it makes the glass a lot more complex, especially if you have a few layers of it behind each other.