A quite good utilization result (see B.1 for the definition) is attained by this method working on a load-balanced mesh (see Appendix B for the definitions). Figures 10.1 for the th80 grid (presented on section 7.2.1) shows the utilization diagram working on a 4-block mesh .
The utilization diagram represent run-time in the x axis and number of processes in the y axis, (4 slaves plus 1 master). The optimum is to have the 4 processes working simultaneously, in green (gray in the b&w version). Red (black) represents wasted process time waiting for communication and Yellow (light gray) means overhead, useless time as well.
Despite its simplicity, this method has the disadvantage that the time step must be limited according to the CFL (5.1) condition due to the explicit step performed in the inter-block boundary.