We at DHT provide machine learning based IT systems performance and capacity evaluations. We model the HW, the OS, as well as the application stack to quantify and optimize the status quo as well as any future workload requirements. Further, we use the models to assess application performance and scalability while changing either the OS or the HW infrastructure. We also use the models to quantify the potential of consolidating server systems and/or workloads. We do this for server systems, clusters, the Cloud, supercomputers, as well as any Big Data environment. As IT installations continue to grow, executing actual empirical studies while acquiring new HW or assessing the impact of workload changes is just not feasible anymore. Hence, a modeling based approach represents basically the only cost effective approach to address performance, capacity, and sizing related IT projects.