there is something definitely going on with Nvidia tech and playstation, there were rumors that sony might had opted out of AMD RT cores coz it was co developed with MS which is much better optimized with DXR, and the rumor was that sony has a third party solution for its RT and is much powerful than AMD solution. so the only options i can think off is PowerVR, custom design or Nvidia.

or highly unlikely.. ND is retooling the engine to support NVidia for future PC release