The performance of your Webform Server system is highly dependent upon the design of the forms being used.
The overall size of your forms and the number of pages, items, and computes that it contains can adversely affect the performance of Webform Server applications. To ensure the best performance, architects of Webform Server solutions should work closely with form designers to ensure that your system is tuned to support your forms. Furthermore, form designers should review the Best practices for form design page on the IBM® Forms wiki located here, and “What's New” documentation to ensure that they are familiar with form design best practices, new functionality, and functionality changes.
In general, you should use XForms-type forms when integrating forms with applications that already use XML, especially if those applications offer XML interfaces. XForms allows you to easily extract XML instance data from the form instead of creating a custom module to extract it. Furthermore, XForms allows you to format the data to match any schema and validate the data against the schema before submission.
Even if your application does not use XML, XForms can still benefit your system. The data model simplifies copying information from one page to another, making wizard-style forms easier to create and manage.
Additionally, forms for high performance applications should consist of five or fewer pages, with each page containing less than 30 items. From a performance perspective, if you need to collect a lot of information it is better to provide a series of smaller forms than to provide one large form. An application that uses five forms with five pages each will outperform an application that uses one form of 25 pages. The form series can still share data, including form pre-population, by passing the data model (or parts of the data model) from one form to another.