High-performance ray tracing of triangle meshes equipped with displacement maps is a challenging task. Existing methods either rely on pre-tessellation, taking full advantage of the hardware but with a poor memory quality tradeoff, or use custom displacement-centric acceleration structures, preserving all the geometric details, but being orders of magnitude slower. We introduce a method that efficiently probes the displacement map space to find intersections without relying on pre-tessellation. Our method combines inverse displacement mapping with on-the-fly surface bounds computation using a novel data structure that models tight bounds over anisotropic axis-aligned regions in the displacement map space. We demonstrate the effectiveness of our approach in a production GPU path tracer, providing from 2x to an order of magnitude speed-up in render time compared to state of the art in the most challenging real-time path tracing scenarios while maintaining a low memory footprint.