SAP BO 4.2 Webi working slow

Hi,

The user working on webi reports complains that it is too slow.
The web when run in HTML is slow and when run in java it is faster.

In HTML it is slower to make any small changes.

Please can you help me in the problem for this behavior and also any resolution for the same.

Thank you very much

SAP BO 4.2 SP5 Patch 2.