At the launch of Turing, Nvidia wasn’t shy about pushing out their newly developed RTX technology. At that time, the Green team made it appear that only RTX cards will support DXR. However, as it appears, Nvidia is going to enable DXR for Pascal Cards from GTX 1060 6GB to GTX 1080TI (Titans are also included), and the newly released Turing GTX cards 1060 and 1060ti are also going to be getting the Ray-Tracing support in a GeForce Driver update in April.
Developers won’t need to release special optimization updates because if the game already has Ray Tracing, then the driver update will simply turn it on.
It goes without saying that the performance with DXR on the GTX cards will be quite poor in comparison to their successors with designated RT cores.