The necessity for high-resolution two-dimensional (2D) simulations in flood modelling often requires excessively long simulation times. This study evaluates the impact of various hardware configurations on Hydrologic Engineering Center-River Analysis System (HEC-RAS) 2D with particular emphasis on Central Processing Unit (CPU) speed, number of cores, Random Access Memory (RAM) capacity, addressing a critical gap in the optimisation of hardware setups for time-efficient simulations. These findings are invaluable for flood modellers and the HEC-RAS community, ultimately supporting more effective flood risk management and decision-making. Additionally, the study examines how different meshes, numerical solution methods, and solving equations perform within these hardware setups, aiming to examine the effects of computational techniques on overall simulation efficiency. Our investigations were carried out using both virtual machines on the Google Cloud Platform and a desktop PC. The findings indicate that optimal performance in HEC-RAS 2D simulations does not necessarily correlate with a higher number of cores or increased RAM. Instead, a well-adjusted configuration with 8 cores and 64 GB of RAM demonstrates superior efficiency. This result questions the usual assumptions about the need for greater computational power and emphasises the value of carefully optimising hardware for fast hydraulic modelling.