Backwards data DVD performance?



Hi All,
I’ve created a bootable DVD+R that holds a hard drive image (created with Symantec DeployCenter 5.6). The disk is a Taiyo Yuden brand, certified at 8x. I burned it using an NEC 3520 drive. I’ve tried applying the image to 3 different models of Dell PCs, and I’m getting some unusual results. As a rule, the older/slower the machine, the FASTER it reads the disk. Can anybody explain why this is happening? Here are the specs on the machines:
Dell OptiPlex GX270: 2.4 GHz P4, 512 MB RAM, Samsung CD-R/W/DVD combo
Dell OptiPlex GX280: 3.2 GHz P4, 1 GB RAM, Hitachi CD-R/W/DVD combo drive
Dell OptiPlex GX620: 4.0 GHz P4, 1 GB RAM, NEC DVD+/-RW (16x) drive

The 270 (the slowest machine) reads the image file from the DVD in about 18 minutes, the 280 takes about 24 minutes, and the 620 takes about 29 minutes. Any ideas why the oldest machine would read the same disc 40% faster than the newest machine?



It’s probably just down to the ripping speeds of the DVD-ROMs which can vary very considerably between models. The NEC is probably locked at 4x speed so would be much slower than the Samsung which will probably read a DVD at 16x (final speed).
My old Asus E616 DVD-ROM will rip at 16x while my new Liteon DVD-ROM would max out at 8x (until I patched the firmware)