PhysX 5.6.1 GPU build 5 Linux libraries now carry an $ORIGIN-relative runpath instead of the build machine's absolute path, so libPhysX_64.so can dlopen libPhysXGpu_64.so on a consumer machine and PhysX no longer falls back to CPU on GPU-capable hardware. Windows is unchanged by the fix but is rebuilt from this tag, so its physics behaviour is worth re-checking (PhysXRuntime_IT).