"Prioritize quality over speed" option in Vegas Pro


What does the "Prioritize quality over speed" option do in the Vegas Pro software?

This option is available when customizing MPEG and MXF Save As types in Vegas Pro. 

When this check box is selected, the encoder will render high-quality video at the expense of increased render times.

You can drag the slider to set your desired video quality. 

When the check box is cleared, the encoder will yield shorter render times by decreasing video quality.

You can drag the slider to set your desired CPU performance. 

Quality settings affect various types of material differently.

With some experimentation, you may find that certain types of scenes can be rendered at lower quality settings (resulting in faster rendering times) with little or no apparent loss of quality. 

For example, changing the default render setting form 31 to 15 can result in a much faster rendering time, with no visible loss in quality in many cases.  

Other material may need the highest possible setting to achieve the desired quality level.