LD3520 1.U8
RIPLOCK REMOVED for fast DVD ripping

LD3520 1.U8 QUIET
RIPLOCK enabled for quiet DVD playback on your PC. Please note, this will only playback slow on pressed DVD’s. DVD-R and +R media will still play at full drive speed. This is a feature of the STOCK NEC firmware.

我想主要是靜音的功能吧!