Blender Cycles for interior architectural visualization

You may already know that Blender is a great tool to create architectural visualization, and the projects and visualization examples featured here at Blender 3D Architect are a clear proof of that. But, It is always nice to be able to watch a detailed demo of how Blender could be used to create interior visualization, which is by far one of the most challenging types of architectural visualization. The guys from eMirage posted an impressive demo showing Blender Cycles in action, dealing with an interior scene.

The quality and speed of the render is amazing, and keeps me wondering which GPUs were used to render this scene.