Composable data centers have been a strong topic of research interest, with potential benefits including higher resource utilization, faster and independent refresh cycles, flexible/optimum resource allocation and better capital and operational costs. In this paper we use a discrete event simulation model to provide a quantitative assessment of the utilization benefits for a composable system versus conventional. We consider a simple multi-server loss queue situation as well as two more realistic scenarios: a mixed memory size demand and a mixed ratio CPU-GPU demand. In all these scenarios, composable systems can provide many tens of percent utilization advantage over more conventional hardware deployments. We also explore the impact of size of the composable resource pool on utilization.