Path Tracing is an advanced form of ray tracing that more accurately accounts for the diffuse interreflections of light and carefully shapes the distributions of light reflected from complex materials. Legacy GPUs were designed for rasterization, which simply translates geometric objects into color pixel values. Legacy GPUs have recently added some ray tracing capabilities on top of rasterization, which they call hybrid rendering. However, legacy GPUs fall short of real time path tracing, which demands a much different architecture. We will talk about how we are building a GPU, Zeus, that's actually able to achieve real-time path tracing.