引自 Tom 的看法，參考一下！

However, speed kills. Unfortunately, the gains afforded by a 16x write speed also mean there are risks that a successful burn has been made, which can cause data to be lost. So, as before, you should stick with a maximum 4x write speed if you are burning a DVD for archiving purposes.

Source: Is It Time to Buy Double-Layer 8.5 GB DVDs?