no * , yes

Improves the performance of highlighting and reorienting large assembly models, regardless of display style (wireframe, hidden line, no hidden line, and shaded).

no - Uses standard highlight.

yes - Uses fast highlight. When you select components, the model geometry (solid, surface) and associated annotations, curves, and cables are highlighted. Datums of a selected component do not highlight unless they are also selected. For models of modest size and complexity, the slight increase in performance may not warrant the additional memory required to support this option.