Before processing a text clip and rendering text effects, you must set crop settings for the text layer, blur settings, text animation, softness, and whether or not you want to use prerendering. The prerendering feature accelerates the rendering process for a text layer.
Set text processing options in the Text Setup menu. To access the Setup menu, click Setup. The Setup controls are described as follows.

Software anti-aliasing values can range from 1 to 64. A higher value increases the sampling rate, but also increases processing time. An anti-aliasing of 1 means no anti-aliasing is performed and the result is a hard edge.
Box Blur has rectangular, rougher edges, but is more economical with processing time, especially if you are working on a rough draft.