Performance is affected by the complexity of a report query. Complex queries require more time for data retrieval than do simple queries. However, because all the data is retrieved before report output is generated, performance is not dependent on the format you choose for the report.
An important way to improve the performance of HTML reports is to manage file size. The larger the HTML files, the longer it takes to load in the browser. You can
align objects
The more unaligned objects you have in a report, the more HTML table entries are created to position the objects an the larger the HTML files.
minimize the number of objects on the report
The more objects in the report, the larger the HTML files.
simplify the use of borders, colors, and font
Formatting is a consideration only when file size is critical. The more complex the formatting, the larger the HTML files.