Quantifying LSM format vs SSM format with P2 Capacity - Same Model; Separate Workspaces

Hi FWPBIDev 

To quantify the performance gains from moving a Power BI semantic model from a small semantic model (SSM) format to a large semantic model (LSM) format, especially in terms of capacity utilization and query performance, there are several steps you can take. First, you should leverage the Power BI Admin Portal to monitor key capacity metrics such as CPU usage, memory consumption, and query performance in both workspaces. By comparing metrics like query duration and response times before and after switching to the LSM, you can directly assess the impact of the model format change. Additionally, using tools like Power BI Query Diagnostics allows you to break down the time spent in different phases of query execution, helping identify any performance bottlenecks. For a more structured approach, consider running load tests to simulate real-world usage, especially focusing on scenarios involving hundreds of subscriptions, which are suspected to cause performance spikes. By triggering the same set of subscriptions in both the SSM and LSM environments, you can track query execution times and system resource utilization to measure the difference in handling high-demand scenarios. Another key area to explore is analyzing subscription activity, which could give insights into whether the spikes are caused by specific report refreshes or concurrent subscriptions. The Power BI Premium Capacity Metrics App can further help track resource consumption in your P2 capacity, providing a more granular view of resource utilization, and allowing you to correlate usage patterns with report activity. Additionally, it’s important to gather feedback from end-users regarding report responsiveness, as subjective user experience can complement the data-driven analysis. By following these steps, you'll be able to quantify performance improvements in terms of reduced resource consumption, better handling of concurrent loads, and overall system efficiency after migrating to the LSM format.