Max burning speed

Using nero vision express 3 and shs 183a burner , under recording settings drop down box i get max, 8x, 6x, 4x, speed choice, using to2 disc (8x). I can select any of the speeds and they are applied in the box if I recheck, but the time it takes to burn disc does not change. How can I get the burning speed to change to a slower speed, log says burn started at 8x
thank you,jerry g