This volume presents current advances in high-performance computing with a focus on efficiency, scalability, and application performance. It provides concrete results from benchmarking, optimization studies, and real-world simulations on leading supercomputer architectures.Key topics include Computational Fluid Dynamics, performance and power evaluations, high-performance data analytics, and the integration of Artificial Intelligence and Machine Learning with large-scale systems. The contributions deliver practical insights into improving sustained simulation performance across diverse domains.Special features include comparative studies, case-based evaluations, and illustrative figures that clarify technical results. By combining methodological approaches with empirical findings, the volume gives its readers tools to optimize their applications for next-generation computing environments.Based on selected papers from the WSSP workshops in Germany and Japan in 2023 and 2024, it offers a perspective on global trends in simulation performance and supercomputing research.