Some areas of the Monitoring UI can be slow, particularly the Dashboards page. Part of the problem is that we don't use React's built in memoization functionality.
Test with payload 4.9.0-0.nightly-2021-08-18-144658 and 4.8.0-0.nightly-2021-08-22-035234, compared UI performance data. Checked alert page, alert rule page and dashboards page, all improve. Detail see attachment
I picked a cluster with wrong build in #c2, retest with payload 4.9.0-0.nightly-2021-08-18-144658 and 4.9.0-0.nightly-2021-08-22-070405 Detail see attachment new performance data
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: OpenShift Container Platform 4.9.0 bug fix and security update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2021:3759