This is working as expected. Each baseline is a snapshot of the project plan, so the more baselines there are, the longer it takes to open/save the project. The amount of time it will increase per baseline is dependent on the size of the project including assignments, durations, number of tasks, etc.
Some options to help with improving performance:
- Only export the current baseline to MSP, as the baseline is a snapshot of the project plan, so the more baselines there are, the longer it takes to open/save the project (The change to only export the current baseline is made in PPM under Administration->Project Management->Settings).
- IMPORTANT: Make sure no projects are currently checked out with baselines when this change is made or you will lose baseline data.
2. The MSP New Driver has improved performance so if using the legacy driver, it's recommended to consider upgrading to the New Driver.
- See KB000093573 for tips in getting started with the new driver
3. See KB000013911
for more information on optimizing performance with the PPM MSP Interface with both the new and legacy drivers.