“Calibrate” your Sammy!
(Or better: cpmpare it to your other scanning drives)
Grab a disc and scan it with your Samsung and another “known good” scanning drive.
At the moment, Samsung DVD writers are not considered as reliable scanners in general. (This at least applies to the 18x series). This thread might help gathering more information about the scanning capabilities compared to other drives.
Post a scan made with your Samsung and your other scanning drive.
Use the same software for that.
Also mention if a drive is externally connected (USB/IDE bridges seem to supress some scanning data, so there are too few errors reported.)
Now go ahead