Sony DVD+-RW DW-D56A Burning Problem

Hey everyone......kinda new here, but I have a question for you all, I bought the Sony DVD+-RW DW-D56A to replace my old NEC 4x dvd burner for my Inspiron 8500 2.4 gig w /1gig memory. I know this burner is actually a Lite-ON SOSW-825x burner....anyway , anyone who has this burner notice if it truely burns at 8x....meaning I also have a Plextor 8x PX-708A burner on my desktop and noticed that it burns full DVD's quicker ( about 9 minutes) then the Sony thats on my laptop ( about 13 minutes) Just wondering if there is anything that can be done or tweeked to make it burn faster. I use Nero Burn on both machines and when it burns it always say about 9 minutes remaining to finish and the Plextor always burns within that time but the Sony seems to burn longer....Any suggestions