Go to the drives tab, and click speed selection, put read at 40 and write at 40, I'll assume you have the 40-40 Plex. and test run it. if you get garbage on your graphics, slow down your write speed a step at a time until you are happy with what you get. If you are using 32X media you need to read at 40 and write at 32, and check for graphic garbage and slow down from that one step at a time.
Jim