A quick and easy SSAS optimisation: turn off flight recorder:
SQL Server Analysis Services Flight Recorder provides a mechanism to record server activity into a short-term log. Information captured by Flight Recorder can be helpful for troubleshooting specific issues, however the load placed on the server when capturing the snapshots and trace events can have a small impact on overall performance. For optimal performance the flight recorder should be disabled unless attempting to capture diagnostic information relevant to troubleshooting a specific problem.
http://byobi.com/2016/01/ever-wondered-whats-captured-in-the-ssas-flight-recorder/