Just before burning, make sure Nero is set to 40x. There should be an option in Nero for checking the media as it burns for your drive (This known as Safeburn in Yamaha drives and SmartBurn in Liteon Drives) and this will limit the speed if senses that the recording quality may be affected if it writes at full speed. It’s called FlextraSpeed in the ASUS drive. My Liteon 40125 (overclocked) limits the writing on 40x Tevion media to 32x and doesn’t give the 40x option unless I disable SmartBurn.
Another thing that affects speed is Zone-CLV. You’ll notice this taking effect when hear the CD spin up a few times during the burning process. When the drive has to spin up for the next zone, it pauses for 5 - 10 seconds. PCAV writing (as in Liteon 40x drives) keeps the drive at the same angular speed until it reaches the top speed and then uses CLV from there on. My Liteon use to take 3m38s with Zone-CLV at 32x and once I got the firmware updated to 40125S, it took 3m14s using PCAV at 32x.
Your computers high speed & good HDD performance should have no effect at all on the burning performance. The Liteon use to take 3m38s at 32x Zone-CLV on a Pentium II 400 with a 20GB hard drive.
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