When the role right "run reports at higher resolution" is assigned to the user, the dashboard will still display data using default resolution in this scenario, 1 hour resolution still used. All reports will use the default resolution.
DX Performance Management CA Performance Management
Edit the dashboard report and change the resolution field to 5 minutes. Once you save the report you should now see 5 minute resolution data for last 30 days.
Additional information regarding running reports at higher resolution is available here: