Great, after spending hours and hours ripping almost all of my DVDs to my server, I find a firmware patch that allows my DVD drive to read movies at about 10 times the speed. Apparently there is a RipLock feature on most DVD drives that prevents high-speed reading of DVD movies. I guess this is great if you're watching a movie, because the drive is spinning very slowly, but not when copying. AnyDVD has a feature to slow down a drive in software, so if I really wanted it slow during movie playback, I can easily set it back to "slow" that way.
Anyway, here is a link to the modified firmwares for NEC drives. I downloaded "Liggy's 3.07 Bitsetting Firmware" – the fast version that removes RipLock – for my NEC 3520 drive.
(I also downloaded binflash to install the firmware: http://binflash.cdfreaks.com/ )