We analytically and numerically study a fourth-order PDE modeling rough crystal
surface diffusion on the macroscopic level. We discuss existence of solutions globally
in time and long-time dynamics for the PDE model. The PDE, originally derived by
Katsevich is the continuum limit of a microscopic model of the surface dynamics,
given by a Markov jump process with Metropolis-type transition rates. We outline
the convergence argument, which depends on a simplifying assumption on the local
equilibrium measure that is valid in the high-temperature regime. We provide
numerical evidence for the convergence of the microscopic model to the PDE in this
regime.