The investigation of coherent phase space structures and other kinetic effects controlling the macroscopic dynamics of collisionless astrophysical plasmas might require the direct solution of the kinetic Vlasov equation, if particle-in-cell- (PIC-) codes are too noisy to resolve fine phase space structures (Buchner in Advanced Methods for Space Simulations, pp. 23-46, 2007). The investigation of the long-term nonlinear evolution of sufficiently large astrophysical plasma systems by solving higher dimensional Vlasov equations requires the development of optimum numerical schemes that allow a massive parallelization. For this sake a four-dimensional (2D2V) unsplit conservative solution scheme was optimized for the use on the ALTIX-4700 computer in the course of the first phase of HLRB project h0842. For the cache-coherent Nonuniform-Memory Architecture (ccNUMA) of the ALTIX-4700 a satisfying performance was achieved only after optimizing the use of the processor-related caches. We demonstrate the achieved performance of a 2D2V Vlasov code on the ALTIX-4700 by means of a Simulation of the nonlinear evolution of two-dimensional plasma instabilities of currents in stellar coronae.