Giant impacts (GI) form the last stage of planet formation and play a key role in determining many aspects like the final structure of planetary systems and the masses and compositions of its constituents. A common choice for numerically solving the equations of motion is the Smoothed Particle Hydrodynamics (SPH) method. We present a new SPH code built on top of the modern gravity code pkdgrav3. The code uses the Fast Multipole Method (FMM) on a distributed binary tree to achieve O(N) scaling and is designed to use modern hardware (SIMD vectorization and GPU). Neighbor finding in SPH is done for a whole group of particles at once and is tightly coupled to the FMM tree code. It therefore preserves the O(N) scaling from the gravity code. A generalized Equation of State (EOS) interface allows the use of various material prescriptions. Currently available are the ideal gas and EOS for the typical constituents of planets: rock, iron, water, and hydrogen/helium mixtures. With the examples of an equal mass merger between two Earth-like bodies and a mantle stripping GI on Mercury (resolved with up to 2 billion particles) we demonstrate the advantages of high-resolution SPH simulations for planet scale impacts.