If your form fillers are using Acrobat 7.0.5 or later, or Adobe Reader 7.0.5 or later, you can choose to have your forms render on the client instead of the server.
Rendering interactive or non-interactive forms that have a flowable layout, whether through Acrobat or Adobe Reader on the client side, achieves better performance than rendering on the server. This is because the Acrobat and Adobe Reader client applications, not the server, perform the rendering operation. Even forms that have a flowable layout and that involve data merging can be rendered on the client.
To render a form at the client, LiveCycle Forms ES must be set to render forms at the client and also generate a shell PDF.
The shell PDF file is a container that lets you deliver an XDP file (as part of the data stream) to the Acrobat or Adobe Reader client. It acts as the shell from which a dynamically rendered PDF is displayed and may contain embedded fonts that the XDP file requires. With the shell PDF file, Acrobat and Adobe Reader are able to open the XDP file and render the PDF on the client.
See also 

Rendering a form design that has a flowable layout on the client