One of the sources of inefficiencies in spark-ignition engines is load control via throttling, which increases pumping work. Hence, many alternative strategies for load control have been studied recently. The concept of variable displacement is one strategy for load control which reduces the load without the need for throttling, avoiding pumping loss. However, there are many differences between the operation of variable displacement and throttling strategies, which cannot be exposed by a first-law-based thermodynamic analysis and are essential for future experimental testing. On that note, this study explores a detailed comparison between both load control strategies using a novel model for second-law-based thermodynamic simulation, with the objective of providing to the literature a comprehensive evaluation of the gas exchange processes under the variable stroke length conditions of a adjustable displacement engine to assist future design and development of these engines. The results demonstrated that the advantages of the variable displacement strategy are beyond the mitigation of pumping losses, reducing residual gas, heat losses and exergy destruction during intake, which combined reached up to 8% less exergetic costs in terms of engine power when comparing variable displacement to the throttling strategy. Possibilities to improve this gain were also identified by the exergetic analysis, which indicated a loss of availability at the blow-down phase of the exhaust process.