SOLIDWORKS 2020 assembly performance has been improved when working with older version files. Previously, components not upgraded to the latest release caused longer open and save times.
This was more noticeable when referenced components had multiple configurations. In SOLIDWORKS 2019 and earlier, only the “master” configuration of a previous version component would load on open and then other configurations were dynamically rebuilt as needed. This was the faster method in the past. With today’s computer hardware (faster CPUs and SSDs), loading file data is fast. In SOLIDWORKS 2020, provided the previous version file configurations were rebuilt and saved properly, it will load all referenced configurations preventing the rebuild process. This method is now faster.
As an example, saving a SOLIDWORKS 2018 assembly in SOLIDWORKS 2019, it would force all the referenced components to upgrade to the current version. The Save As dialog would show a list of the components with green highlighting. You couldn’t deselect the referenced component check boxes.
In SOLIDWORKS 2020, there is a new option under System Options > External References called ‘Force referenced document to save to current major version‘. By default this is enabled so it acts like previous versions. However if you deselect the option, the referenced documents will no longer save to the the current version.
Now saving the same assembly in SOLIDWORKS 2020 will no longer save all the referenced files.
This allows you to keep referenced components in an earlier version and can eliminate the need to bulk upgrade files to a newer version for best performance using the PDM File Version Upgrade Utility or Task Scheduler Convert Files task.
NOTE: If a referenced part or sub-assembly requires a rebuild on opening the assembly (i.e. in-context relations that are updated), it will require saving which will upgrade to the newer version. These components will show up in the Save dialog.