Assembly Performance Improvements Assembly performance is improved when: Searching with Include sub-folders selected. To select this option, click Tools > Options > External References > Reference Documents specified in File Locations > Include sub-folders. For assemblies that contain parts with multiple imported bodies and body level appearances: Opening a file Changing a configuration Applying, modifying, or removing an appearance Rolling back or rolling forward assembly items Saving assemblies is faster as only changed model data is saved. This improvement is noticeable in very large assemblies. Previously, SOLIDWORKS saved all model data when an assembly or a component changed. Parent topicAssemblies